Is this a prescription you are trying to fill by phone? If it's a med you've been taking, there's no reason to see the physician in person. Is there something in the medication that might harm you if you have covid? I can see, for example, that a doc might be wary of blood thinning meds, and there are a ton of supplements, foods, and drugs that have some effect on that, for someone with covid and its clotting action. Did you ask why?
This might depend on where you live. It is possibly legal, but also likely unethical.
Did your doctor give you a specific reason for refusing medication without a COVID test?