Check if last seen stat has changed

[jacobsentertainment]

Is it possible to check if the "last seen" state can be checked, I have one temperature sensor that I would like to check.

My idea is to have an script running based on a switch and an sensor triggering an switch.
Switch 1 = heating switch
Sensor = floor temperature
Switch 2 = thermostat pause

If heating switch is longer on then 15 minutes then set thermostat to pause. It doesn't sound complicated and probably it isn't but i can't see the solution and I had some looks trough the samples and trough this part of the forum but kind find any good start of that matches my needs.
If someone can push me in the right direction..