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 (
    97246, 97247, 97248, 97249, 97250, 97251, 
    97252, 97253, 97254, 97255, 97256, 
    97257, 97258, 97259, 97260, 97261, 
    97262, 97263, 97264, 97265, 97266, 
    97267, 97268, 97269, 97270, 97271, 
    97272, 97273, 97274, 97275
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00072

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 (97246,97247,97248,97249,97250,97251,97252,97253,97254,97255,97256,97257,97258,97259,97260,97261,97262,97263,97264,97265,97266,97267,97268,97269,97270,97271,97272,97273,97274,97275)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97246
97247
97248
97249
97250
97251
97252
97253
97254
97255
97256
97257
97258
97259
97260
97261
97262
97263
97264
97265
97266
97267
97268
97269
97270
97271
97272
97273
97274
97275