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 (
    96050, 96052, 96054, 96056, 96058, 96060, 
    96063, 96065, 96067, 96069, 96071, 
    96073, 96075, 96077, 96079, 96080, 
    96081, 96084, 96085, 96088, 96089, 
    96092, 96093, 96096, 96097, 96100, 
    96101, 96104, 96394, 96395, 96396, 
    96397, 96409, 96410, 96429, 96432, 
    96433, 96442, 96443, 96444, 96445, 
    96446, 96447, 96448, 96449, 96450, 
    96451, 96452
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00041

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 (96050,96052,96054,96056,96058,96060,96063,96065,96067,96069,96071,96073,96075,96077,96079,96080,96081,96084,96085,96088,96089,96092,96093,96096,96097,96100,96101,96104,96394,96395,96396,96397,96409,96410,96429,96432,96433,96442,96443,96444,96445,96446,96447,96448,96449,96450,96451,96452)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96050
96052
96054
96056
96058
96060
96063
96065
96067
96069
96071
96073
96075
96077
96079
96080
96081
96084
96085
96088
96089
96092
96093
96096
96097
96100
96101
96104
96394
96395
96396
96397
96409
96410
96429
96432
96433
96442
96443
96444
96445
96446
96447
96448
96449
96450
96451
96452