Amazon ElastiCache is a fully managed in-memory caching service compatible with Redis or Memcached that can improve the performance of web applications by allowing you to retrieve information from fast, managed, in-memory caches, instead of relying solely on slower disk-based databases. It also offers automatic scaling to handle traffic spikes, making it an ideal solution for the scenario described. Amazon RDS is a relational database service, not a caching service, and does not offer in-memory caching capabilities. Amazon CloudFront is primarily used as a Content Delivery Network (CDN) for caching static web content geographically closer to users, but would not be appropriate for caching database query results. Amazon Elastic Beanstalk is an orchestration service for deploying infrastructure which includes a variety of services, but itself is not a caching solution.