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 (
    11021, 11035, 11215, 11302, 11514, 11134, 
    11555, 11264, 11294, 11353, 11374, 
    11590, 11214, 11259, 11295, 11224, 
    11298, 11392, 11408, 11083, 11344, 
    11465, 11473, 11601, 11369, 11372, 
    11130, 11234, 11138, 11209, 11296, 
    11026, 11144, 11268, 11377, 11090, 
    11524, 11235, 11410, 11305
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00115

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 (11021,11035,11215,11302,11514,11134,11555,11264,11294,11353,11374,11590,11214,11259,11295,11224,11298,11392,11408,11083,11344,11465,11473,11601,11369,11372,11130,11234,11138,11209,11296,11026,11144,11268,11377,11090,11524,11235,11410,11305)) and (`softwarepirmam_hewadelivard_cscart_4`.`cscart_product_descriptions`.`lang_code` = 'en'))",
      "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"
      ]
    }
  }
}