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 (
    96385, 96386, 96387, 96388, 96389, 96390, 
    96391, 96398, 96399, 96400, 98600, 
    98601, 98603, 98607, 98609, 98611, 
    98612, 98613, 98616, 98626, 98628, 
    98630, 98631, 98632, 98633, 98635, 
    98637, 98639, 98640, 98641, 98644, 
    98645, 98646, 98647, 98649, 98650, 
    98652, 98653, 98657, 98658, 98659, 
    98661, 98663, 98665, 98666, 98667, 
    98668, 98669
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00152

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "21.63"
    },
    "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": "16.83",
        "eval_cost": "4.80",
        "prefix_cost": "21.63",
        "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 (96385,96386,96387,96388,96389,96390,96391,96398,96399,96400,98600,98601,98603,98607,98609,98611,98612,98613,98616,98626,98628,98630,98631,98632,98633,98635,98637,98639,98640,98641,98644,98645,98646,98647,98649,98650,98652,98653,98657,98658,98659,98661,98663,98665,98666,98667,98668,98669)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96385
96386
96387
96388
96389
96390
96391
96398
96399
96400
98600
98601
98603
98607
98609
98611
98612
98613
98616
98626
98628
98630
98631
98632
98633
98635
98637
98639
98640
98641
98644
98645
98646
98647
98649
98650
98652
98653
98657
98658
98659
98661
98663
98665
98666
98667
98668
98669