Is there a faster way to get a random record from a MySQL table via ActiveRecord?

In a Rails application, I use this to get a random row from a MySQL table:

contact = Contact.find(:all, :limit => 1, :order => 'RAND()')[0]

      

        
        
        
      

    

Despite the fact that the table contains about 20,000 rows, it takes a couple of seconds. Does anyone know a faster way?

Update

Also tried to just run SQL in the console ...

SELECT * FROM `contacts` ORDER BY RAND() LIMIT 1

      

        
        
        
      

    

It still takes a long time, like two or three seconds.