Preheat oven to 350°F (175°C). In a food processor, combine graham cracker crumbs, 1 cup shredded coconut, 2 tbsp granulated sugar, and 1/4 tsp sea salt. Pulse until the coconut is finely chopped and well combined with the crumbs.

Add the melted butter and pulse until the mixture resembles wet sand. Press the mixture firmly and evenly into the bottom and up the sides of a 9-inch pie plate. You can use the bottom of a glass or your knuckles to ensure a compact crust.

Bake the crust for 8-10 minutes, or until lightly golden brown. Remove from oven and let cool slightly while you prepare the filling.

In a large mixing bowl, whisk together the sweetened condensed milk, full-fat coconut milk, key lime juice, key lime zest, egg yolks, and 1/4 tsp sea salt until completely smooth and well combined. The mixture will thicken slightly as you whisk.

Pour the filling into the pre-baked and slightly cooled crust.

Return the pie to the preheated oven and bake for 15-20 minutes, or until the center is just set but still slightly wobbly. Do not overbake; the pie will continue to set as it cools.

Remove the pie from the oven and let it cool completely on a wire rack at room temperature.

Once cooled, cover the pie loosely with plastic wrap and refrigerate for at least 4 hours, or preferably overnight, to allow it to fully chill and set.

If using, toast the optional 1/4 cup shredded coconut in a dry skillet over medium-low heat for 3-5 minutes, stirring frequently, until golden brown. Let cool.

Slice the chilled pie and serve with a dollop of whipped cream or meringue, if desired, and sprinkle with toasted coconut flakes.