I just started a demo of DxO PhotoLab, and I can't find my keystoning tools.

Keystoning tools are now part of the DxO ViewPoint plug-in to DxO PhotoLab. You can start a demo of DxO ViewPoint 2 from the Help menu entry.

A free DxO ViewPoint 1 license is included with an upgrade to DxO PhotoLab from earlier versions of OpticsPro.