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 (
    98810, 98811, 98812, 98813, 98814, 98874, 
    98875, 98876, 98877, 98878, 98879, 
    98880, 98881, 98886, 98887, 98888, 
    99056, 99057, 99058, 99059, 99060, 
    99061, 99062, 99063, 99064, 99065, 
    99067, 99077, 99078, 99081, 99082, 
    99110, 99111, 99112, 99113, 99114, 
    99115, 99116, 99117, 99118, 99119, 
    99120, 99121, 99122, 99123, 99124, 
    99125, 99126
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00063

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.62"
    },
    "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": "16.82",
        "eval_cost": "4.80",
        "prefix_cost": "21.62",
        "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 (98810,98811,98812,98813,98814,98874,98875,98876,98877,98878,98879,98880,98881,98886,98887,98888,99056,99057,99058,99059,99060,99061,99062,99063,99064,99065,99067,99077,99078,99081,99082,99110,99111,99112,99113,99114,99115,99116,99117,99118,99119,99120,99121,99122,99123,99124,99125,99126)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
98810
98811
98812
98813
98814
98874
98875
98876
98877
98878
98879
98880
98881
98886
98887
98888
99056
99057
99058
99059
99060
99061
99062
99063
99064
99065
99067
99077
99078
99081
99082
99110
99111
99112
99113
99114
99115
99116
99117
99118
99119
99120
99121
99122
99123
99124
99125
99126