Another way would be to index the metas in db just like title and description are indexed and adjust the query to search also in those flelds...but:
1.You would have to regenerate the indexes in db anyway for all the items.(this also if you change the description via sql without editing the item)
2.The metas are stored in meta_fields table and the item's metas in item_meta table, so you should index the columns s_value, fk_i_field_id and fk_i_item_id from the last and s_name from the first table depending by fk_i_field_id column from the above first table.
The easiest way would be to query directly into these tables without using mysql fulltext search . That would impact your query times and server load.