Preheat the oven to 350º F and line 24 muffin cups with liners.
Mix graham cracker crumbs, butter, and sugar. Add 1 tablespoon of the mixture to each muffin cup and press down. Bake for 5 minutes and set aside.
Cream together cream cheese and sugar for 2 minutes until smooth, scraping the bowl as needed.
Add sour cream, key lime juice, and vanilla, and mix well.
Add eggs one at a time, beating for 1 minute after each addition. Stir in flour until just combined.
Spoon the batter into the muffin cups.
Bake for 25-30 minutes, until set.
Cool for 10-15 minutes, then remove from the pan and cool completely on a wire rack.