Not sure if too many folks round here use keyshot as this is the first time I've seen it mentioned.

If keyshot is capable of importing FBX (which it probably is), and if you have the Poser game dev, then you can try that. As far as I know there is no other way of importing or exporting a model with materials intact, unless some 3rd party script exists somewhere. You would need to re-apply them manually if it doesn't read fbx. 

If you have zbrush, there is a zbrush-keyshot bridge coming with the release of zb 4r7 (for around $250). You might look into setting up a workflow that combines goz, poser, zb and keyshot. However, Poser still isn't capable of importing or exporting textures from zbrush via goz either, while DS is, so DS is also a possibility if you're not in the anti-DS crowd. In Poser they still have to be set up manually (cause Poser likes to keep it oldskool like that)