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 (
    98234, 98235, 98236, 98237, 98238, 98239, 
    98240, 98241, 98242, 98243, 98244, 
    98245, 98246, 98247, 98248, 98249, 
    98250, 98251, 98252, 98253, 98254, 
    98255, 98256, 98257, 98258, 98259, 
    98260, 98261, 98262, 98263, 98264, 
    98265, 98266, 98267, 98268, 98269, 
    98270, 98271, 98272, 98273, 98274, 
    98275, 98276, 98277, 98278, 98279, 
    98280, 98281
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00045

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 (98234,98235,98236,98237,98238,98239,98240,98241,98242,98243,98244,98245,98246,98247,98248,98249,98250,98251,98252,98253,98254,98255,98256,98257,98258,98259,98260,98261,98262,98263,98264,98265,98266,98267,98268,98269,98270,98271,98272,98273,98274,98275,98276,98277,98278,98279,98280,98281)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98234
98235
98236
98237
98238
98239
98240
98241
98242
98243
98244
98245
98246
98247
98248
98249
98250
98251
98252
98253
98254
98255
98256
98257
98258
98259
98260
98261
98262
98263
98264
98265
98266
98267
98268
98269
98270
98271
98272
98273
98274
98275
98276
98277
98278
98279
98280
98281