AFAIK there is no such thing in the Axe FX firmware. If there were I would expect it to be in the setup menu under utilities. The manual doesn't mention any such functionality.
Anyways, I would strongly suspect that it's not needed. Most modern SOCs have protections against thermal faults so they would turn off before there could be any damage to the chip. Even if the chipset used in the Axe FX should have no such mechanism, any competent engineer would design it in a way to ensure that it's guaranteed to be safe as long as you don't exceed the allowed environmental temperature (50°C/122°F) - and as Fractal has a pretty much perfect track record for hardware design you should be able to rest easy.
There is a CPU limit of 90% for presets, described in section chapter 5 of the manual under "preset CPU limits". But the drawbacks of actually going over 90% are only described as "audio performance may be compromised" and "at extremely high CPU usage levels, the Axe-Fx III may become unstable". This sounds more like you have to worry about running out of resources to do the processing fast enough and less about overheating the unit.
As an aside, "operation temperature" is an ambiguous term in a complex system such as the Axe FX. There's probably a multitude of temperature sensors on the chipset; I would assume at the very least one per core (DSP1, DSP2, FPGA, USB, ...) and possibly further ones for submodules of the cores. A generic "whole package" temperature would probably have limited use as temperature can vary widely over the package.