Preheat oven to 350°F (175°C). In a bowl, combine graham cracker crumbs, 0.33 cups sugar, and melted butter. Press mixture into the bottom of a 9-inch springform pan to form crust.
Bake crust for 10 minutes, then remove and allow to cool.
In a large bowl, beat softened cream cheese with 1 cup sugar until smooth and creamy.
Add eggs one at a time, beating well after each addition.
Mix in key lime juice, key lime zest, sour cream, and vanilla extract until fully incorporated.
Pour cheesecake filling over cooled crust, smoothing the top.
Bake for 45-50 minutes or until edges are set and center is slightly jiggly.
Turn off oven, crack the door, and let cheesecake cool inside for 1 hour.
Refrigerate the cheesecake for at least 4 hours before serving.
Notes
Garnish with whipped cream and lime slices for an extra fresh presentation.