I walked into the room as this scene was playing when I was a kid, and I’ve never been able to track it down. It was released before 1997, probably filmed after 1970.
There’s a mostly empty bar/saloon, with a cowboy playing cards. As the scene continues, the cowboys turn into skeletons, and then those skeletons begin to turn into white powder or dust in the wind. I remember it as a mostly ambient scene, perhaps a dream sequence. I don’t think it was a horror movie. It was probably set in the present, because I recall the scene cutting to some kind of black car afterward.
I live in Canada, although my wife’s American mom recalls the scene but can’t remember the movie either. It could also be a television show, or a made-for-tv movie. That’s all I’ve got. :