Search API with Panels in Drupal 7
Here is your answer: Page manager search. It works with the Search API module. Here is an excerpt about it from the module's project page:

... adds the ability for Page manager pages to be searchable via the Drupal core Search module or the Search API module.
Support for:

Drupal core Search module.
Search API module (via the Entity API module)


Note: this is a new module.