Combine graham cracker crumbs, sugar and butter in a medium size bowl. Mix until uniform. Press crust mixture over the bottom and up the sides of a 10-inch tart pan with removable bottom. Bake for 10-12 minutes, until crust is golden brown. Allow to cool.
Combine cream cheese and condensed milk in the bowl of an electric mixer fitted with a paddle attachment (a hand mixer could be used too). Mix on medium speed until uniform. Mix in Key Lime Curd on low speed until combined. Pour mixture into prepared crust and refrigerate at least 4 hours before serving. Can be made a day ahead. Serve with sweetened whipped cream and sliced lime garnish.