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 (
    97326, 97327, 97328, 97329, 97330, 97331, 
    97332, 97333, 97334, 97335, 97336, 
    97337, 97338, 97339, 97340, 97341, 
    97342, 97343, 97344, 97345, 97346, 
    97347, 97348, 97349, 97350, 97351, 
    97352, 97353, 97354, 97355
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00079

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "13.52"
    },
    "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": 30,
      "rows_produced_per_join": 30,
      "filtered": "100.00",
      "cost_info": {
        "read_cost": "10.52",
        "eval_cost": "3.00",
        "prefix_cost": "13.52",
        "data_read_per_join": "114K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ],
      "attached_condition": "((`nuie_scalesta_net`.`cscart_product_descriptions`.`product_id` in (97326,97327,97328,97329,97330,97331,97332,97333,97334,97335,97336,97337,97338,97339,97340,97341,97342,97343,97344,97345,97346,97347,97348,97349,97350,97351,97352,97353,97354,97355)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97326
97327
97328
97329
97330
97331
97332
97333
97334
97335
97336
97337
97338
97339
97340
97341
97342
97343
97344
97345
97346
97347
97348
97349
97350
97351
97352
97353
97354
97355