The smart search module is only capable of indexing data from documents (of standard document types [not containers]) and from custom tables (this custom table needs to be created by custom tables module -
Custom tables module overview)
You can create a new custom table via the custom table module and keep your data in this
custom table that can be indexed by the smart search module . Would this be an option for you? If not, I’m afraid you would need to modify smart search module web part and add results from your custom table to the resulting dataset, since smart search module is currently not able to index data from your custom table in that was not created via custom table module of Kentico CMS.
Also... don't forget to rebuild your search index.