If we're studying the psychology of behavior in any life form, we can't allow ourselves to fall into boxy or linear thinking. It's a trap we're prone to.
Pupils dilate differently in response to light, drugs, love, food, being Nala in the Lion King, getting punched in the eye, concussions, and genetic manipulation.
You have to look at other body language components along with the lick. This is a lick is missing some stress signals that may mean it's less anxiety driven or only partly anxious. A video would be more informative.
There is no whale eye here (whites of the eyes), eyebrows are 'somewhat' relaxed (not totally sleepy relaxed, but not ridgidly flexed either), ears are not flattened/down in an anxious position (see the linked article below for stressed vs relaxed face and note Clara's whale eye, folded ears, and eyebrows in the stressed image).