SELECT 
  lang.name, 
  lang.value 
FROM 
  cscart_language_values lang 
WHERE 
  lang.lang_code = 'en' 
  AND lang.name IN (
    'sg_modern_theme.contact_us', 'sg_modern_theme.contact_hours', 
    'sg_modern_theme.send_us_a_message', 
    'sg_modern_theme.send_message', 
    'sg_modern_theme.response_note', 
    'sg_modern_theme.thanks_for_contact_msg', 
    'sg_modern_theme.contact_us', 'sg_modern_theme.contact_hours', 
    'sg_modern_theme.send_us_a_message', 
    'sg_modern_theme.send_message', 
    'sg_modern_theme.response_note', 
    'sg_modern_theme.thanks_for_contact_msg'
  )

Query time 0.00045

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost": 0.01122386,
    "nested_loop": [
      {
        "table": {
          "table_name": "lang",
          "access_type": "range",
          "possible_keys": ["PRIMARY"],
          "key": "PRIMARY",
          "key_length": "392",
          "used_key_parts": ["lang_code", "name"],
          "loops": 1,
          "rows": 6,
          "cost": 0.01122386,
          "filtered": 100,
          "attached_condition": "lang.lang_code = 'en' and lang.`name` in ('sg_modern_theme.contact_us','sg_modern_theme.contact_hours','sg_modern_theme.send_us_a_message','sg_modern_theme.send_message','sg_modern_theme.response_note','sg_modern_theme.thanks_for_contact_msg','sg_modern_theme.contact_us','sg_modern_theme.contact_hours','sg_modern_theme.send_us_a_message','sg_modern_theme.send_message','sg_modern_theme.response_note','sg_modern_theme.thanks_for_contact_msg')"
        }
      }
    ]
  }
}