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 (
    87283, 87291, 87806, 87807, 87812, 87815, 
    87821, 87764, 87770, 87773, 87777, 
    87788, 87794, 87281, 87289, 86862, 
    87754, 86860, 87809, 87811, 87814, 
    87817, 87824, 87808, 87810, 87813, 
    87816, 87823, 87779, 87793
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00073

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (87283,87291,87806,87807,87812,87815,87821,87764,87770,87773,87777,87788,87794,87281,87289,86862,87754,86860,87809,87811,87814,87817,87824,87808,87810,87813,87816,87823,87779,87793)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}