Yes, that is someone’s foot touching a moving lava flow without combusting.
It’s a screenshot from this video – notice the person just lightly taps the foot, because this lava with unusual chemistry is still pretty hot. Still, you can get close, unlike around a runny red Hawaiian lava flow.
Be sure your speakers are on when you watch this snap-crackle-and-pop volcano in action.
Here is Ol Doinyo Lengai’s Global Volcanism Program page from the Smithsonian.