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 (
    99902, 99903, 99904, 99905, 99906, 99907, 
    99908, 99909, 99910, 99911, 99912, 
    99913, 99914, 99915, 99916, 99917, 
    99918, 99932, 99933, 99934, 99935, 
    99936, 99937, 99938, 99939, 99940, 
    99941, 99942, 99943, 99944, 99945, 
    99946, 99947, 99948, 99949, 99950, 
    99951, 99952, 99953, 99954, 99955, 
    99956, 99957, 99958, 99959, 99960, 
    99961, 99962
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00107

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "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 (99902,99903,99904,99905,99906,99907,99908,99909,99910,99911,99912,99913,99914,99915,99916,99917,99918,99932,99933,99934,99935,99936,99937,99938,99939,99940,99941,99942,99943,99944,99945,99946,99947,99948,99949,99950,99951,99952,99953,99954,99955,99956,99957,99958,99959,99960,99961,99962)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}