Records with expired TTL are not being deleted

Some reasons why its not working. Is your field a String or Number? as in your search, your using string which it should be a number.

• Be sure that you activated TTL on the table and the related settings are correct:
• The item must contain the attribute that you specified when you activated TTL on the table.
• The TTL attribute's value must have the data type Number.
• The TTL attribute's value must be a timestamp in seconds in Unix epoch time format. For more information, see Unix time on Wikipedia.
• The TTL attribute value must be a datetimestamp with an expiration of no more than five years in the past.
• The TTL processes run on the table only when there's enough spare capacity so that these processes don't interfere with table operations. If the table or table partitions use most of the allocated capacity, then TTL processes might not run.

https://repost.aws/knowledge-center/dynamodb-expired-ttl-not-deleted