You can use the data files from https://bugs.launchpad.net/maria/+bug/938977 to reproduce this.

Mysql 5.1.49 and MySQL 5.1.61
Handle this query in 5 seconds on my EC2 m2.4xlarge instance.

I was getting ready to move to MariaDB on production.
Installed mariadb 5.3.5, ran this query, waited 3+ minutes, and it still didn't complete, so had to revert back to mysql 5.1

SELECT `data_mediagallery`.`filetype` AS `filetype`, `data_mediagallery`.`id` AS `id`, `data_mediagallery`.`metadata` AS `metadata`, `data_mediagallery`.`title` AS `title`, `data_mediagallery`.`vhost` AS `vhost` FROM data_mediagallery
INNER JOIN
`geo` USE INDEX ( `morton` )
ON
`data_mediagallery`.`id` = `geo`.`foreignid`
AND
`geo`.`datatype` = 1
AND
`geo`.`morton` BETWEEN getGeoMorton( -89.055209, -173.81254 ) AND getGeoMorton( 89.505209, 173.36254 )
AND
`geo`.`latitude` BETWEEN -89.055209 AND 89.505209
AND
`geo`.`longitude` BETWEEN -173.81254 AND 173.36254

AND
`geo`.`vhost` = 123
WHERE (data_mediagallery.context = 1) AND (data_mediagallery.hidden = 0) AND (data_mediagallery.status IN (3)) AND (data_mediagallery.vhost = 123) ORDER BY `data_mediagallery`.`upload` DESC LIMIT 1000, 500;

It's very similar to the query in the previous bug.

The geoMorton function is available there also.