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 (
    92799, 92800, 92801, 92802, 92803, 92804, 
    92805, 92806, 92807, 92808, 92809, 
    92810, 92811, 92812, 92813, 92814, 
    92815, 92816, 92817, 92818, 92819, 
    92820, 92821, 92822, 92823, 92824, 
    92825, 92826, 92827, 92828
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00074

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 (92799,92800,92801,92802,92803,92804,92805,92806,92807,92808,92809,92810,92811,92812,92813,92814,92815,92816,92817,92818,92819,92820,92821,92822,92823,92824,92825,92826,92827,92828)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}

Result

product_id short_description full_description
92799
92800
92801
92802
92803
92804
92805
92806
92807
92808
92809
92810
92811
92812
92813
92814
92815
92816
92817
92818
92819
92820
92821
92822
92823
92824
92825
92826
92827
92828