Preheat the oven to 250 degrees F (120 degrees C). Melt butter in a saucepan. Whisk in Worcestershire sauce and hot sauce until well blended. Whisk in seasoned salt, garlic powder, onion powder, cayenne, and celery seed. Combine corn cereal squares, wheat cereal squares, and pretzels in a large oven-safe bowl or roasting pan. Drizzle the sauce over the mix with a spoon, stirring frequently, until well coated. Bake in the preheated oven, stirring every 15 minutes, until hot and crunchy, about 1 hour and 15 minutes. Turn off the oven, stir the mix, and leave the oven door cracked open with the mix still inside. Let cool inside for 45 to 60 minutes. Store in airtight containers.