SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.short_description, 
  IF(
    cscart_product_descriptions.short_description = '' 
    OR cscart_product_descriptions.short_description IS NULL, 
    cscart_product_descriptions.full_description, 
    ''
  ) AS full_description 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    91008, 91019, 91020, 91031, 91032, 91044, 
    91045, 85842, 85843, 84291, 84333, 
    84334, 91004, 91005, 91016, 91017, 
    91028, 91029, 91040, 91041, 91042, 
    86190, 86191, 86213, 86214, 86522, 
    86523, 86798, 86799, 90008, 84667, 
    85821, 84347, 84659, 84660, 88689, 
    88736, 86489, 86765, 86188, 86211, 
    86520, 86796, 82603, 82605, 85079, 
    85165, 85211
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00110

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "range",
      "possible_keys": [
        "PRIMARY",
        "product_id"
      ],
      "key": "PRIMARY",
      "used_key_parts": [
        "product_id",
        "lang_code"
      ],
      "key_length": "9",
      "rows_examined_per_scan": 48,
      "rows_produced_per_join": 48,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "data_read_per_join": "183K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (91008,91019,91020,91031,91032,91044,91045,85842,85843,84291,84333,84334,91004,91005,91016,91017,91028,91029,91040,91041,91042,86190,86191,86213,86214,86522,86523,86798,86799,90008,84667,85821,84347,84659,84660,88689,88736,86489,86765,86188,86211,86520,86796,82603,82605,85079,85165,85211)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}