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 (
    93659, 93660, 93661, 93662, 93663, 93664, 
    93665, 93666, 93667, 93668, 93669, 
    93670, 93671, 93672, 93673, 93674, 
    93675, 93676, 93677, 93678, 93679, 
    93680, 93681, 93682, 93683, 93684, 
    93685, 93686, 93687, 93688
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00044

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 (93659,93660,93661,93662,93663,93664,93665,93666,93667,93668,93669,93670,93671,93672,93673,93674,93675,93676,93677,93678,93679,93680,93681,93682,93683,93684,93685,93686,93687,93688)) and (`nuie_scalesta_net`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}