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 (
    96326, 96327, 96328, 96329, 96330, 96331, 
    96332, 96333, 96334, 96335, 96336, 
    96337, 96338, 96339, 96340, 96341, 
    96342, 96343, 96344, 96345, 96346, 
    96347, 96348, 96601, 96602, 96603, 
    96604, 96605, 96606, 96607, 96608, 
    96609, 96610, 96611, 96612, 96613, 
    96614, 96615, 96616, 96617, 96618, 
    96619, 96620, 96621, 96622, 96623, 
    96624, 96625
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00112

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 (96326,96327,96328,96329,96330,96331,96332,96333,96334,96335,96336,96337,96338,96339,96340,96341,96342,96343,96344,96345,96346,96347,96348,96601,96602,96603,96604,96605,96606,96607,96608,96609,96610,96611,96612,96613,96614,96615,96616,96617,96618,96619,96620,96621,96622,96623,96624,96625)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96326
96327
96328
96329
96330
96331
96332
96333
96334
96335
96336
96337
96338
96339
96340
96341
96342
96343
96344
96345
96346
96347
96348
96601
96602
96603
96604
96605
96606
96607
96608
96609
96610
96611
96612
96613
96614
96615
96616
96617
96618
96619
96620
96621
96622
96623
96624
96625