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 (
    93369, 93370, 93371, 93372, 93373, 93374, 
    93375, 93376, 93377, 93378, 93379, 
    93380, 93381, 93382, 93383, 93384, 
    93385, 93386, 93387, 93388, 93389, 
    93390, 93391, 93392, 93393, 93394, 
    93395, 93396, 93397, 93398
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00074

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 (93369,93370,93371,93372,93373,93374,93375,93376,93377,93378,93379,93380,93381,93382,93383,93384,93385,93386,93387,93388,93389,93390,93391,93392,93393,93394,93395,93396,93397,93398)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
93369
93370
93371
93372
93373
93374
93375
93376
93377
93378
93379
93380
93381
93382
93383
93384
93385
93386
93387
93388
93389
93390
93391
93392
93393
93394
93395
93396
93397
93398