I don’t know if you can get blood tests “just because” from any of the pharmacy clinics or urgent care places, but might be worth calling them to ask.
You can, however, get blood tests done through Life Extension Foundation. They have a wide range of tests available at quite reasonable prices (self-pay, not through insurance).
The basic weight loss panel has most of the tests that would be relevant to keto (Insulin, A1C, glucose, lipid panel, hormones, etc.). There are many other tests available if you need info for other related (or non-related) conditions. Another test that’s worth having done occasionally is Vitamin D 25-Hydroxy. Vitamin D is increasingly being recognized as a really important nutrient for a whole range of conditions, and many (perhaps most) of us don’t get enough sun exposure to produce what we need.
Once you purchase a given test or tests, you simply schedule a draw from the closest LabCorp (LEF works with them for the testing), and they do the draw, and send the results to LEF. They then mail you a copy of the results, and also make them available on their website as PDF. Pretty easy.