Preheat the air fryer to 400°F (200°C) for about 5 minutes.
Spread 1/4 cup of marinara sauce evenly on each slice of bread.
Sprinkle 1/2 cup of shredded mozzarella cheese over the sauce on each slice.
Arrange the sliced pepperoni evenly on top of the cheese.
Sprinkle garlic powder, dried oregano, and red pepper flakes (if using) over the toppings.
Place the prepared pizza toast in the air fryer basket in a single layer.
Cook for 5-7 minutes or until the cheese is melted and bubbly, and the edges of the bread are golden brown.
Carefully remove the pizza toast from the air fryer and let it cool for a minute.
Garnish with fresh basil leaves if desired, then slice and serve warm.