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 (
    97722, 97723, 97724, 97725, 97726, 97727, 
    97765, 97766, 97767, 97768, 97769, 
    97770, 97771, 97772, 97773, 97775, 
    97776, 97777, 97783, 97784, 97785, 
    97787, 97788, 97789, 97799, 97800, 
    97801, 98145, 98147, 98151
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00063

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 (97722,97723,97724,97725,97726,97727,97765,97766,97767,97768,97769,97770,97771,97772,97773,97775,97776,97777,97783,97784,97785,97787,97788,97789,97799,97800,97801,98145,98147,98151)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
97722
97723
97724
97725
97726
97727
97765
97766
97767
97768
97769
97770
97771
97772
97773
97775
97776
97777
97783
97784
97785
97787
97788
97789
97799
97800
97801
98145
98147
98151