What is the absolute maximum temperature of a ceramic capacitor while not operating? (non-operational maximum)
With material degradation due to over-temperature, you won't find any hard and fast rules. Why? Because the material degradation depends on a curve that increase with temperature. The curve deals with mechanical and chemical changes that happen, most of these effects are known by manufacturers and sometimes they will share this data, but you have to ask. Most users don't need this and so only rated temperatures are provided. Let's dig into what we know about the temperature of the part.
Almost any electronic part (and this cap) can be put through 260C for at least 30sec and follow a reflow profile like this:

Source: https://static6.arrow.com/aropdfconversion/7287aad747c6d8a778a4cf32f86caa437f956283/19-cl03a104kp3nnnc.pdf
From this we know that the part can survive 260C, but the manufacturer doesn't want the part to dwell at that temperature for more than 30s.
The temperature of 150C for 1 hr is okay and then the part degrades over it's lifetime for a X5R or less so for an X7R and almost no degradation over lifetime for a C0G.

Source: https://static6.arrow.com/aropdfconversion/7287aad747c6d8a778a4cf32f86caa437f956283/19-cl03a104kp3nnnc.pdf
The manufacturer didn't tell us anything beyond this, so if we wanted to know more, then the capacitors would need to be tested by a cognizant engineer or the manufacturer. The manufacturer may have additional testing information, but they might not. They are trying to guarantee their part under a specific set of conditions so it is unlikely that they would have additional information but it doesn't hurt to ask.
The other disappointing thing is we don't know (from the datasheet) if extending the time spent a 150C further degrades the part (double the degradation over time), only one test is shown.
So from this I would personally surmise that I don't want this part to get to 150C for more than 1hr. Also it should be noted that an X7R or C0G (which generally have higher operating temperature ratings) do not degrade with time and support 125C operating ranges in most cases. So I would go with a higher temperature rated part or contact the manufacturer. If cost is an issue then finding the rating would be a good idea, if cost is not then just go with the X7R or C0G.
Also the application is also worth considering, if this is for a bypass cap, then tolerance does not need to be accounted for in most cases, conversely a filter application (DC DC converter or analog filter does need a high tolerance part).