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 (
    98024, 98025, 98026, 98027, 98028, 98029, 
    98515, 98521, 98522, 99054, 99055, 
    99189, 99190, 99191, 99239, 99356, 
    99357, 99358, 99359, 99360, 99361, 
    99362, 99363, 99364, 99365, 99366, 
    99374, 99375, 99376, 99377, 99378, 
    99379, 99380, 99381, 99382, 99383, 
    99384, 99385, 99386, 99387, 99388, 
    99389, 99390, 99391, 99392, 99393, 
    99394, 99395
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00049

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 (98024,98025,98026,98027,98028,98029,98515,98521,98522,99054,99055,99189,99190,99191,99239,99356,99357,99358,99359,99360,99361,99362,99363,99364,99365,99366,99374,99375,99376,99377,99378,99379,99380,99381,99382,99383,99384,99385,99386,99387,99388,99389,99390,99391,99392,99393,99394,99395)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98024
98025
98026
98027
98028
98029
98515
98521
98522
99054
99055
99189
99190
99191
99239
99356
99357
99358
99359
99360
99361
99362
99363
99364
99365
99366
99374
99375
99376
99377
99378
99379
99380
99381
99382
99383
99384
99385
99386
99387
99388
99389
99390
99391
99392
99393
99394
99395