SELECT 
  cscart_product_point_prices.product_id, 
  MIN(
    cscart_product_point_prices.point_price
  ) AS point_price 
FROM 
  cscart_product_point_prices 
WHERE 
  cscart_product_point_prices.product_id IN (150, 148, 149, 5) 
  AND cscart_product_point_prices.lower_limit = 1 
  AND cscart_product_point_prices.usergroup_id IN (0, 0, 1)

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.00345856,
    "nested_loop": [
      {
        "table": {
          "table_name": "cscart_product_point_prices",
          "access_type": "range",
          "possible_keys": ["unique_key", "src_k"],
          "key": "unique_key",
          "key_length": "8",
          "used_key_parts": ["lower_limit", "usergroup_id", "product_id"],
          "loops": 1,
          "rows": 1,
          "cost": 0.00345856,
          "filtered": 100,
          "index_condition": "cscart_product_point_prices.lower_limit = 1 and cscart_product_point_prices.product_id in (150,148,149,5) and cscart_product_point_prices.usergroup_id in (0,0,1)"
        }
      }
    ]
  }
}