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 (
    732, 731, 727, 725, 724, 723, 809, 810, 
    720, 718, 717, 716, 715, 713, 709, 708, 
    707, 705, 701, 697, 696, 695
  ) 
  AND cscart_product_descriptions.lang_code = 'ar'

Query time 0.00047

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "15.41"
    },
    "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": 22,
      "rows_produced_per_join": 22,
      "filtered": "100.00",
      "index_condition": "((`betaatif_store`.`cscart_product_descriptions`.`product_id` in (732,731,727,725,724,723,809,810,720,718,717,716,715,713,709,708,707,705,701,697,696,695)) and (`betaatif_store`.`cscart_product_descriptions`.`lang_code` = 'ar'))",
      "cost_info": {
        "read_cost": "13.21",
        "eval_cost": "2.20",
        "prefix_cost": "15.41",
        "data_read_per_join": "83K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description"
      ]
    }
  }
}