Some help doing 301 redirection within htaccess

Hi,
I'm migrating an old site from custom php to wordpress and I'm stuck doing some redirection expression in the new site.
I would really appreciate some help.

I would need to go from
http://www.mysite.com/lang/es/artist.php?aid=3
to
http://www.mysite.com/artistas/artistname/

I've done many other redirection for pages and categories so I know that my htaccess is working, the problem must be in the expression
This what I got so far
To be honest I don't really know how to use a 2 level folder in my RewriteRule

RewriteEngine on
RewriteCond %{QUERY_STRING} aid=3
RewriteRule ^/lang/es/artist\.php$ http://www.mysite.com/artistas/artistname/? [L,R=301]

Thanks for your time