To change the default cache experiration time please execute:

$desired_expiration_time = 500; // 500 seconds
\Drupal::configFactory()->getEditable('prefetch_cache.settings')->set('time_to_live', $desired_expiration_time)->save();

The module gives also the ability to define custom cache tags for the cache entries for each request, so that even custom forms might be cached and invalidated.
For this a CacheTagsGenerator implementing the CacheTagsGeneratorInterface should be created and should be defined as a service with the tag
- { name: prefetch_cache_cache_tags_generator }
so that it is automatically added to the chain of Cache Tags Generators.