How to filter the primary key from kafka topic which format upsert avro encode?

[Taymindis]

I have created the table shown as below

CREATE TABLE IF NOT EXISTS student
(primary key (_id))
include key as _id
WITH (
   connector='kafka',
   properties.bootstrap.server='kafka:9092',
   topic='owener.student'
)
FORMAT UPSERT ENCODE AVRO (
   schema.registry = 'http://schema-reg:8081'
);

But the primary key (_id) data is \x00000027608e0ee2

My actual data from kafka key should be studentid: 33

If i want to filter _id = 33, how should i do ?