[Skunkworks] SEO .htaccess rewrite rule

Hi skunks, i have been struggling on how to create a rewrite rule for this link on the htaccess file on my root folder anyone out there has a clue? Ive been to many online rewrite rule sir\tes where i feed this link and the resultant rule is simply not picked up by the mod_rewirite apache module. http://www.mydomain.com/index.php?category=mycategory&mykey=mykey