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 (
    94460, 94461, 94462, 94751, 94752, 94753, 
    94754, 94755, 94756, 94757, 94758, 
    94762, 94764, 95565, 95567, 95568, 
    95570, 95572, 95573, 95576, 95577, 
    95582, 95583, 95584, 95585, 95586, 
    95639, 95654, 95934, 95937
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00039

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 (94460,94461,94462,94751,94752,94753,94754,94755,94756,94757,94758,94762,94764,95565,95567,95568,95570,95572,95573,95576,95577,95582,95583,95584,95585,95586,95639,95654,95934,95937)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94460
94461
94462
94751
94752
94753
94754
94755
94756
94757
94758
94762
94764
95565
95567
95568
95570
95572
95573
95576
95577
95582
95583
95584
95585
95586
95639
95654
95934
95937