That is totally normal for the 8700K and absolutely in the right ball park. A better CPU cooler can drop temps, but not sure what you are running...
An easy way to tell whether you are having any issues is to run Prime95 version 26.6 and do the blend test and check temps...if under 80 but even better in the 70's degrees you are more than fine. Again dependant on CPU cooler as the temps can be even lower depending on what CPU cooler you are running..