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 (
    98393, 98394, 98395, 98396, 98397, 98398, 
    98399, 98400, 98401, 98402, 98403, 
    98404, 98405, 98406, 98411, 98412, 
    98413, 98421, 98422, 98424, 98425, 
    98426, 98427, 98428, 98429, 98432, 
    98433, 98434, 98435, 98436, 98437, 
    98438, 98439, 98440, 98441, 98442, 
    98443, 98446, 98447, 98449, 98450, 
    98451, 98452, 98453, 98455, 98456, 
    98476, 98477, 98478, 98479, 98480, 
    98481, 98483, 98484, 98485, 98486, 
    98487, 98488, 98489, 98490, 98491, 
    98492, 98493, 98494, 98495, 98503, 
    98504, 98505, 98506, 98507, 98508, 
    98759, 98769, 98770, 98771, 98772, 
    98897, 99066, 99508, 99509, 99510, 
    99512, 99513, 99514, 99516, 99517, 
    99518, 100480, 100481, 100484, 100485, 
    100486, 100700, 100701, 100702, 100703
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00081

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "43.24"
    },
    "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": 96,
      "rows_produced_per_join": 96,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "33.64",
        "eval_cost": "9.60",
        "prefix_cost": "43.24",
        "data_read_per_join": "366K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (98393,98394,98395,98396,98397,98398,98399,98400,98401,98402,98403,98404,98405,98406,98411,98412,98413,98421,98422,98424,98425,98426,98427,98428,98429,98432,98433,98434,98435,98436,98437,98438,98439,98440,98441,98442,98443,98446,98447,98449,98450,98451,98452,98453,98455,98456,98476,98477,98478,98479,98480,98481,98483,98484,98485,98486,98487,98488,98489,98490,98491,98492,98493,98494,98495,98503,98504,98505,98506,98507,98508,98759,98769,98770,98771,98772,98897,99066,99508,99509,99510,99512,99513,99514,99516,99517,99518,100480,100481,100484,100485,100486,100700,100701,100702,100703)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98393
98394
98395
98396
98397
98398
98399
98400
98401
98402
98403
98404
98405
98406
98411
98412
98413
98421
98422
98424
98425
98426
98427
98428
98429
98432
98433
98434
98435
98436
98437
98438
98439
98440
98441
98442
98443
98446
98447
98449
98450
98451
98452
98453
98455
98456
98476
98477
98478
98479
98480
98481
98483
98484
98485
98486
98487
98488
98489
98490
98491
98492
98493
98494
98495
98503
98504
98505
98506
98507
98508
98759
98769
98770
98771
98772
98897
99066
99508
99509
99510
99512
99513
99514
99516
99517
99518
100480
100481
100484
100485
100486
100700
100701
100702
100703