Using paper towels, pat shrimp dry. In a medium bowl, toss shrimp with salt, baking soda, and sugar until evenly coated. Arrange shrimp on a wire rack set over a rimmed baking sheet and refrigerate, uncovered, for 20 to 30 minutes.
Preheat a 6-quart air fryer to 400℉ (205ºC) for 5 minutes. Using paper towels, pat shrimp dry again, transfer to a large bowl, and toss with melted butter to coat.
Arrange shrimp in air fryer basket in a single layer, making sure shrimp are not touching each other. Cook, undisturbed, until shrimp are cooked through and have just turned opaque, about 4 minutes. Serve immediately.
