Send a alert after a time condition

Send a alert after a time condition

I have a customer who has a door sensor and wants to receive an alert when the door has been open for more than 3 minutes.
Every time I receive information from the sensor, I record this information and have an analysis that runs every 2 minutes checking if the door has been open for more than 3 minutes.
This solution works, but my analysis quota has increased considerably. Is there a better way to do this feature?