Yes, your Ubigi data plan does have an expiration date, depending on the type of plan you have. If you are on a yearly subscription, it will expire one year from the activation date. For one-off subscription, your connectivity expires at the end of the validity period indicated on the product (this period can last from 1 day to 30 days). Make sure to check the expiration details in your account to stay connected!
See also: How to cancel the Ubigi data plan linked to my Toyota?