SELECT 
  SQL_CALC_FOUND_ROWS products.product_id, 
  descr1.product as product, 
  companies.company as company_name, 
  popularity.total as popularity, 
  MIN(
    IF(
      prices.percentage_discount = 0, 
      prices.price, 
      prices.price - (
        prices.price * prices.percentage_discount
      )/ 100
    )
  ) as price, 
  absolute_rating.rating AS absolute_vendor_rating, 
  products.product_type, 
  products.parent_product_id, 
  products.list_price as list_price, 
  MAX(
    100 - (
      (prices.price * 100) / products.list_price
    )
  ) AS sales_discount 
FROM 
  cscart_products as products 
  LEFT JOIN cscart_product_features_values ON cscart_product_features_values.product_id = products.product_id 
  AND cscart_product_features_values.lang_code = 'en' 
  LEFT JOIN cscart_product_features ON cscart_product_features_values.feature_id = cscart_product_features.feature_id 
  LEFT JOIN cscart_product_descriptions as descr1 ON descr1.product_id = products.product_id 
  AND descr1.lang_code = 'en' 
  LEFT JOIN cscart_product_prices as prices ON prices.product_id = products.product_id 
  AND prices.lower_limit = 1 
  LEFT JOIN cscart_product_prices as prices_2 ON prices.product_id = prices_2.product_id 
  AND prices_2.lower_limit = 1 
  AND prices_2.price < prices.price 
  AND prices_2.usergroup_id IN (0, 0, 1) 
  LEFT JOIN cscart_companies AS companies ON companies.company_id = products.company_id 
  INNER JOIN cscart_products_categories as products_categories ON products_categories.product_id = products.product_id 
  INNER JOIN cscart_categories ON cscart_categories.category_id = products_categories.category_id 
  AND (
    cscart_categories.usergroup_ids = '' 
    OR FIND_IN_SET(
      0, cscart_categories.usergroup_ids
    ) 
    OR FIND_IN_SET(
      1, cscart_categories.usergroup_ids
    )
  ) 
  AND cscart_categories.status IN ('A', 'H') 
  AND cscart_categories.storefront_id IN (0, 1) 
  LEFT JOIN cscart_product_popularity as popularity ON popularity.product_id = products.product_id 
  LEFT JOIN cscart_absolute_rating AS absolute_rating ON absolute_rating.object_id = products.company_id 
  AND absolute_rating.object_type = 'company' 
  LEFT JOIN cscart_product_sales ON cscart_product_sales.product_id = products.product_id 
  AND cscart_product_sales.category_id = products_categories.category_id 
WHERE 
  1 
  AND companies.status IN ('A') 
  AND (
    products.usergroup_ids = '' 
    OR FIND_IN_SET(0, products.usergroup_ids) 
    OR FIND_IN_SET(1, products.usergroup_ids)
  ) 
  AND products.status IN ('A') 
  AND prices.usergroup_id IN (0, 0, 1) 
  AND prices_2.price IS NULL 
  AND products.parent_product_id = 0 
  AND products.product_type != 'D' 
GROUP BY 
  products.product_id 
HAVING 
  sales_discount > 0 
  AND price < list_price 
ORDER BY 
  sales_discount desc, 
  products.product_id ASC 
LIMIT 
  0, 4

Query time 0.00354

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 3.77117318,
    "having_condition": "sales_discount > 0 and price < products.list_price",
    "filesort": {
      "sort_key": "max(100 - prices.price * 100 / products.list_price) desc, products.product_id",
      "temporary_table": {
        "nested_loop": [
          {
            "table": {
              "table_name": "products",
              "access_type": "ALL",
              "possible_keys": ["PRIMARY", "status", "idx_parent_product_id"],
              "loops": 1,
              "rows": 248,
              "cost": 0.0555528,
              "filtered": 97.9903717,
              "attached_condition": "products.parent_product_id = 0 and (products.usergroup_ids = '' or find_in_set(0,products.usergroup_ids) or find_in_set(1,products.usergroup_ids)) and products.`status` = 'A' and products.product_type <> 'D'"
            }
          },
          {
            "block-nl-join": {
              "table": {
                "table_name": "companies",
                "access_type": "ALL",
                "possible_keys": ["PRIMARY"],
                "loops": 243.016129,
                "rows": 2,
                "cost": 0.071108091,
                "filtered": 50,
                "attached_condition": "companies.`status` = 'A'"
              },
              "buffer_type": "flat",
              "buffer_size": "191KiB",
              "join_type": "BNL",
              "attached_condition": "companies.company_id = products.company_id"
            }
          },
          {
            "table": {
              "table_name": "prices",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["u985510652_gaurav.products.product_id"],
              "loops": 486.0322581,
              "rows": 1,
              "cost": 0.469631335,
              "filtered": 97.63779449,
              "attached_condition": "prices.lower_limit = 1 and prices.usergroup_id in (0,0,1)"
            }
          },
          {
            "table": {
              "table_name": "prices_2",
              "access_type": "ref",
              "possible_keys": [
                "usergroup",
                "product_id",
                "lower_limit",
                "usergroup_id"
              ],
              "key": "usergroup",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["u985510652_gaurav.products.product_id"],
              "loops": 486.0322581,
              "rows": 1,
              "cost": 0.469631335,
              "filtered": 97.63779449,
              "attached_condition": "trigcond(prices_2.price is null) and trigcond(prices_2.lower_limit = 1 and prices_2.price < prices.price and prices_2.usergroup_id in (0,0,1))",
              "not_exists": true
            }
          },
          {
            "table": {
              "table_name": "cscart_product_features_values",
              "access_type": "ref",
              "possible_keys": [
                "lang_code",
                "product_id",
                "idx_product_feature_variant_id"
              ],
              "key": "product_id",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["u985510652_gaurav.products.product_id"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.462749692,
              "filtered": 100,
              "attached_condition": "trigcond(cscart_product_features_values.lang_code = 'en')",
              "using_index": true
            }
          },
          {
            "table": {
              "table_name": "descr1",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "product_id"],
              "key": "PRIMARY",
              "key_length": "9",
              "used_key_parts": ["product_id", "lang_code"],
              "ref": ["u985510652_gaurav.products.product_id", "const"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.503919958,
              "filtered": 100,
              "attached_condition": "trigcond(descr1.lang_code = 'en')"
            }
          },
          {
            "table": {
              "table_name": "popularity",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "total"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["u985510652_gaurav.products.product_id"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.425276758,
              "filtered": 100
            }
          },
          {
            "table": {
              "table_name": "absolute_rating",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY"],
              "key": "PRIMARY",
              "key_length": "102",
              "used_key_parts": ["object_id", "object_type"],
              "ref": ["u985510652_gaurav.products.company_id", "const"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.425276758,
              "filtered": 100,
              "attached_condition": "trigcond(absolute_rating.object_type = 'company')"
            }
          },
          {
            "table": {
              "table_name": "products_categories",
              "access_type": "ref",
              "possible_keys": ["PRIMARY", "pt"],
              "key": "pt",
              "key_length": "3",
              "used_key_parts": ["product_id"],
              "ref": ["u985510652_gaurav.products.product_id"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.462749692,
              "filtered": 100,
              "using_index": true
            }
          },
          {
            "table": {
              "table_name": "cscart_categories",
              "access_type": "eq_ref",
              "possible_keys": ["PRIMARY", "c_status", "p_category_id"],
              "key": "PRIMARY",
              "key_length": "3",
              "used_key_parts": ["category_id"],
              "ref": ["u985510652_gaurav.products_categories.category_id"],
              "loops": 474.5511811,
              "rows": 1,
              "cost": 0.425276758,
              "filtered": 100,
              "attached_condition": "(cscart_categories.usergroup_ids = '' or find_in_set(0,cscart_categories.usergroup_ids) or find_in_set(1,cscart_categories.usergroup_ids)) and cscart_categories.`status` in ('A','H') and cscart_categories.storefront_id in (0,1)"
            }
          }
        ]
      }
    }
  }
}