Scale the EC2 instance during high traffic and use Amazon SNS for order notifications, with the database subscribed to the SNS topic.

Utilize Amazon SQS to queue orders and deploy EC2 instances in an Auto Scaling group with an Application Load Balancer to process orders from the queue into the database.

Leverage Amazon SNS for order notifications with the database endpoint subscription, and implement EC2 instances in an Auto Scaling group with an Application Load Balancer to process orders.

Queue orders using Amazon SQS when the EC2 CPU threshold is reached, and process them into the database using EC2 instances in an Auto Scaling group with scheduled scaling and an Application Load Balancer.