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 (
    94673, 94674, 94694, 94695, 94696, 94697, 
    94698, 94699, 94700, 94701, 94702, 
    94707, 94708, 94750, 94751, 94752, 
    94753, 94754, 94755, 94756, 94757, 
    94758, 94759, 94760, 94761, 94762, 
    94763, 94764, 94765, 94816
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00076

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 (94673,94674,94694,94695,94696,94697,94698,94699,94700,94701,94702,94707,94708,94750,94751,94752,94753,94754,94755,94756,94757,94758,94759,94760,94761,94762,94763,94764,94765,94816)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
94673
94674
94694
94695
94696
94697
94698
94699
94700
94701
94702
94707
94708
94750
94751
94752
94753
94754
94755
94756
94757
94758
94759
94760
94761
94762
94763
94764
94765
94816