Is it possible to lock a single Google Slides presentation slide

This is currently not a Google Docs feature (and not possible) based on online documentation and no better answer. Apparently, this worked at one point in Google Docs, but it required viewers to use Google Talk (and this combination was buggy at the time).

An alternative I went with is PowerPoint 2010, which comes with a feature to broadcast slideshows to users over the Internet.

You can right click on the slide and choos "Skip Slide"