SELECT 
  cscart_product_descriptions.product_id, 
  cscart_product_descriptions.unit_name 
FROM 
  cscart_product_descriptions 
WHERE 
  cscart_product_descriptions.product_id IN (101, 63) 
  AND cscart_product_descriptions.lang_code = 'en'

Query time 0.00099

JSON explain

{
  "query_block": {
    "select_id": 1,
    "cost_info": {
      "query_cost": "51.60"
    },
    "table": {
      "table_name": "cscart_product_descriptions",
      "access_type": "ALL",
      "rows_examined_per_scan": 248,
      "rows_produced_per_join": 4,
      "filtered": "2.00",
      "cost_info": {
        "read_cost": "51.10",
        "eval_cost": "0.50",
        "prefix_cost": "51.60",
        "data_read_per_join": "22K"
      },
      "used_columns": [
        "product_id",
        "lang_code",
        "unit_name"
      ],
      "attached_condition": "((`mobikul_delivery_boy_livedemo`.`cscart_product_descriptions`.`product_id` in (101,63)) and (`mobikul_delivery_boy_livedemo`.`cscart_product_descriptions`.`lang_code` = 'en'))"
    }
  }
}