Preheat the oven to 350 degrees. Line a 13- by 9-inch baking pan with foil, allowing several inches of excess to hang over the sides. Spray foil with cooking spray and set pan aside.

Combine the graham cracker crumbs, butter, and sugar in a small mixing bowl and mix until thoroughly combined. Press into the bottom of the prepared pan.

Top the graham cracker layer with the coconut, followed by the candy corn, butterscotch chips, and pecans. Pour the sweetened condensed milk over everything, then sprinkle with sea salt (if using). Bake 22 to 25 minutes, until golden on top. Cool magic bars completely in the pan set on a wire rack, then slice into bars and serve.