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 (
    91330, 91328, 91329, 91327, 91426, 87745, 
    91326, 87748, 87744, 91425, 91424, 
    87751, 91325, 87743, 87747, 91422, 
    91423, 87750, 87746, 91421, 87749
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00093

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "9.47"
    },
    "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": 21,
      "rows_produced_per_join": 21,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "7.37",
        "eval_cost": "2.10",
        "prefix_cost": "9.47",
        "data_read_per_join": "80K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (91330,91328,91329,91327,91426,87745,91326,87748,87744,91425,91424,87751,91325,87743,87747,91422,91423,87750,87746,91421,87749)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}