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, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (
    3745, 3943, 3623, 3670, 3684, 3645, 3437, 
    3637, 3682, 3767, 3950, 3644, 3659, 
    3766, 3864, 3940, 3436, 3739, 3444, 
    3785, 3442, 3787, 3945, 3438, 3770, 
    3865, 3793, 3447, 3450, 3772, 3795, 
    3788, 3439, 3446, 3687, 3860, 3794, 
    3858, 3869, 3948
  ) 
  AND cscart_product_descriptions.lang_code = 'ar'

Query time 0.00104

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "28.33"
    },
    "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": 40,
      "rows_produced_per_join": 40,
      "filtered": "100.00",
      "index_condition": "((`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`product_id` in (3745,3943,3623,3670,3684,3645,3437,3637,3682,3767,3950,3644,3659,3766,3864,3940,3436,3739,3444,3785,3442,3787,3945,3438,3770,3865,3793,3447,3450,3772,3795,3788,3439,3446,3687,3860,3794,3858,3869,3948)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'ar'))",
      "cost_info": {
        "read_cost": "24.33",
        "eval_cost": "4.00",
        "prefix_cost": "28.33",
        "data_read_per_join": "182K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "short_description",
        "full_description",
        "unit_name"
      ]
    }
  }
}