Mysql - Create sample data from existing rows

I have a table with about 50K rows. I need to multiply this data 10 fold to have at least 5M rows for testing the performance. Now, its taken me several long minutes to import 50K from a CSV file so I don't want to create a 5M record file and then import it into SQL.

Is there a way to duplicate the existing rows over and over again to create 5M records? I don't mind if the rows are identical, they should just have a diferrent id which is the Primary (Auto Increment) column.

I'm currently doing this on XAMPP with phpMyAdmin.