SELECT 
  description 
FROM 
  cscart_image_gallery_settings_description 
WHERE 
  id = 289 
  AND lang_code = 'ru' 
  AND type = 'P'

Query time 0.00040

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "table_name": "cscart_image_gallery_settings_description",
      "access_type": "const",
      "possible_keys": ["PRIMARY", "id"],
      "key": "PRIMARY",
      "key_length": "13",
      "used_key_parts": ["id", "lang_code", "type"],
      "ref": ["const", "const", "const"],
      "rows": 1,
      "filtered": 100
    }
  }
}