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 (
    6902, 7017, 6920, 7110, 7272, 6833, 6841, 
    7147, 7153, 6837, 7000, 6831, 6835, 
    7155, 6891, 6952, 6917, 6836, 6839, 
    7146, 6847, 6834, 6838, 7059, 7118, 
    6931, 7130, 6849, 6900, 6848, 6832, 
    7116, 7078, 6886, 7308, 6872, 7160, 
    6888, 7274, 7129
  ) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00123

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 (6902,7017,6920,7110,7272,6833,6841,7147,7153,6837,7000,6831,6835,7155,6891,6952,6917,6836,6839,7146,6847,6834,6838,7059,7118,6931,7130,6849,6900,6848,6832,7116,7078,6886,7308,6872,7160,6888,7274,7129)) 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"
      ]
    }
  }
}