post your query in a readable format

then...

foreach table in your query post the results of the following:

   show table status like '<table name>';
   explain <table name>;
   show indexes from <table name>;

finally...

post the explain plan of your query

if you have problems formatting the output of any of the above try using the \G modifier

http://pento.net/2009/02/27/the-g-modifier-in-the-mysql-command-line-client/