I am looking for a database that could handle (create an index on a column in a reasonable time and provide results for select queries in less than 3 sec) more than
What you want to look at is the table size limit the database software imposes. For example, as of this writing, MySQL InnoDB has a limit of 64 TB per table, while PostgreSQL has a limit of 32 TB per table; neither limits the number of rows per table. If correctly configured, these database systems should not have trouble handling tens or hundreds of billions of rows (if each row is small enough), let alone 500 million rows.
For best performance handling extremely large amounts of data, you should have sufficient disk space and good disk performance—which can be achieved with disks in an appropriate RAID—and large amounts of memory coupled with a fast processor(s) (ideally server-grade Intel Xeon or AMD Opteron processors). Needless to say, you'll also need to make sure your database system is configured for optimal performance and that your tables are indexed properly.