I braved a CVS to pick up a prescription for someone in isolation, and while I was there decided to get a flu shot. I had to tick some boxes and hand over my insurance card, then wait a couple minutes for the nurse to come out, but it only took a few minutes -- my total indoor exposure time (including the prescription pickup) was less than 15 minutes.

I thought I was lucky that the nurses were still there that late in the evening, but it turns out that location is open 24 hours/day, apparently including for flu shots. You can schedule in advance, including doing the paperwork online, which is great if you want to do it at like 23:30 when hardly anyone's there.

Good experience, recommended. Just remember to wear a short-sleeved shirt. :-P