I have a script where I would like to show 5 random items from a particular seller, and 5 random items from other sellers:

PHP Code:
$sql "SELECT * FROM items WHERE seller = 'johndoe' LIMIT 5";
$sql "SELECT * FROM items WHERE seller != 'johndoe' LIMIT 5"
The 'seller' column is indexed and I have over 300,000 items.
The first query runs through super quick (0.01 seconds).
The second query takes 10 seconds.

I see that the Not Equals or "!=" does not work on an index. Is there a way to speed this up somehow?

Kind regards