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 (
    96302, 96303, 96712, 96716, 96721, 96729, 
    96730, 96731, 96736, 96737, 96750, 
    96753, 96754, 96768, 96769, 96788, 
    97012, 97020, 97036, 97043, 97049, 
    97051, 97055, 97810, 97814, 97816, 
    97817, 97834, 97838, 97840, 97988, 
    97992, 98030, 98034, 98159, 98163, 
    98167, 98224, 98225, 98226, 98227, 
    98228, 98234, 98235, 98236, 98237, 
    98238, 98239
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00095

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 (96302,96303,96712,96716,96721,96729,96730,96731,96736,96737,96750,96753,96754,96768,96769,96788,97012,97020,97036,97043,97049,97051,97055,97810,97814,97816,97817,97834,97838,97840,97988,97992,98030,98034,98159,98163,98167,98224,98225,98226,98227,98228,98234,98235,98236,98237,98238,98239)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}