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 (
    95400, 95401, 95434, 95435, 95436, 95437, 
    95438, 95439, 95440, 95441, 95704, 
    95705, 95728, 95729, 95730, 95731, 
    95732, 95733, 95734, 95735, 96170, 
    96171, 96172, 96173, 96537, 96559, 
    96560, 96561, 97057, 97058
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00068

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 (95400,95401,95434,95435,95436,95437,95438,95439,95440,95441,95704,95705,95728,95729,95730,95731,95732,95733,95734,95735,96170,96171,96172,96173,96537,96559,96560,96561,97057,97058)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
95400
95401
95434
95435
95436
95437
95438
95439
95440
95441
95704
95705
95728
95729
95730
95731
95732
95733
95734
95735
96170
96171
96172
96173
96537
96559
96560
96561
97057
97058