Preheat your oven to 350ºF and line 24 muffin cups with liners.
Mix graham cracker crumbs, melted butter, and sugar. Add 1 tablespoon of crumbs to each liner, press down, and bake for 5 minutes. Set aside.
Beat cream cheese and sugar until smooth, scraping the bowl as needed.
Mix in sour cream, key lime juice, and vanilla until well combined.
Add eggs one at a time, beating after each, then gently stir in flour.
Fill muffin cups with batter and bake for 25-30 minutes until set. Cool, remove from pan, and let cool fully on a wire rack.