The laser would only need a break if your cooler’s cooling capacity is not sufficient for the amount of heat the tube produces and/or the ambient temperature is too hot such that the cooler is not able to cool the heated water coming back from the laser tube.
It depends on which cooler you have, but most coolers trigger an alarm when its water temperature is getting too hot. You could then use this alarm to pause (stop) the laser.
Edit: I am not aware of a software solution as in built in to Lightburn, but a possible electrical solution would be to use a timer OFF relay connected to the status output of your controller (if it has any) or maybe even a push button and then using a normally open output of the timer off connected to the water protection input of the controller. The way this works is that the trigger (Q) of the timer will stay high for 30 minutes and then switch to low, triggering the controller. When pressing the button or using the status output of the controller, the timer gets reset and will let the laser continue for another 30 minutes.