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 (
    96258, 96259, 96262, 96265, 96266, 96267, 
    96268, 96269, 96270, 96271, 96272, 
    96273, 96274, 96275, 96276, 96277, 
    96278, 96279, 96280, 96281, 96282, 
    96287, 96288, 96289, 96292, 96574, 
    96575, 96577, 96578, 96579, 96580, 
    96584, 96585, 96586, 96587, 96588, 
    96589, 96590, 96591, 96592, 96593, 
    96594, 96595, 96596, 100547, 100548, 
    100549, 100551
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00100

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 (96258,96259,96262,96265,96266,96267,96268,96269,96270,96271,96272,96273,96274,96275,96276,96277,96278,96279,96280,96281,96282,96287,96288,96289,96292,96574,96575,96577,96578,96579,96580,96584,96585,96586,96587,96588,96589,96590,96591,96592,96593,96594,96595,96596,100547,100548,100549,100551)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96258
96259
96262
96265
96266
96267
96268
96269
96270
96271
96272
96273
96274
96275
96276
96277
96278
96279
96280
96281
96282
96287
96288
96289
96292
96574
96575
96577
96578
96579
96580
96584
96585
96586
96587
96588
96589
96590
96591
96592
96593
96594
96595
96596
100547
100548
100549
100551