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 (
    96626, 96627, 96628, 96629, 96668, 96669, 
    96670, 96671, 96672, 96673, 96674, 
    96675, 96676, 96678, 96680, 96681, 
    96682, 96683, 96686, 96687, 96688, 
    96689, 96690, 96691, 96692, 96694, 
    97015, 97016, 97017, 97022, 97023, 
    97024, 97025, 97026, 97027, 97028, 
    97029, 97030, 97031, 97032, 97033, 
    97039, 97040, 97045, 97046, 97083, 
    97219, 97220
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00092

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 (96626,96627,96628,96629,96668,96669,96670,96671,96672,96673,96674,96675,96676,96678,96680,96681,96682,96683,96686,96687,96688,96689,96690,96691,96692,96694,97015,97016,97017,97022,97023,97024,97025,97026,97027,97028,97029,97030,97031,97032,97033,97039,97040,97045,97046,97083,97219,97220)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
96626
96627
96628
96629
96668
96669
96670
96671
96672
96673
96674
96675
96676
96678
96680
96681
96682
96683
96686
96687
96688
96689
96690
96691
96692
96694
97015
97016
97017
97022
97023
97024
97025
97026
97027
97028
97029
97030
97031
97032
97033
97039
97040
97045
97046
97083
97219
97220