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 (
    98754, 98755, 98756, 98757, 99653, 99654, 
    99655, 99656, 99657, 99658, 99659, 
    99660, 99661, 99662, 99663, 99664, 
    99665, 99666, 99667, 99668, 100504, 
    100505, 100506, 100507, 100508, 100509, 
    100510, 100511, 100512, 100513, 100514, 
    100515, 100516, 100517, 100518, 100519, 
    100520, 100521, 100522, 100523, 100524, 
    100525, 100526, 100527, 100528, 100529, 
    100530, 100531, 100532, 100533, 100534, 
    100535, 100642, 100644, 100646, 100648, 
    101022, 101023, 101024, 101025, 101026, 
    101027, 101028, 101029, 101030, 101031, 
    101032, 101033, 101034, 101035
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00118

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "31.53"
    },
    "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": 70,
      "rows_produced_per_join": 70,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "24.53",
        "eval_cost": "7.00",
        "prefix_cost": "31.53",
        "data_read_per_join": "266K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (98754,98755,98756,98757,99653,99654,99655,99656,99657,99658,99659,99660,99661,99662,99663,99664,99665,99666,99667,99668,100504,100505,100506,100507,100508,100509,100510,100511,100512,100513,100514,100515,100516,100517,100518,100519,100520,100521,100522,100523,100524,100525,100526,100527,100528,100529,100530,100531,100532,100533,100534,100535,100642,100644,100646,100648,101022,101023,101024,101025,101026,101027,101028,101029,101030,101031,101032,101033,101034,101035)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98754
98755
98756
98757
99653
99654
99655
99656
99657
99658
99659
99660
99661
99662
99663
99664
99665
99666
99667
99668
100504
100505
100506
100507
100508
100509
100510
100511
100512
100513
100514
100515
100516
100517
100518
100519
100520
100521
100522
100523
100524
100525
100526
100527
100528
100529
100530
100531
100532
100533
100534
100535
100642
100644
100646
100648
101022
101023
101024
101025
101026
101027
101028
101029
101030
101031
101032
101033
101034
101035