Improving query performance on mysql star catalog
Instead of SELECT *, try selecting the fields you need (unless you need all of them!): SELECT id, magG, ... FROM
Try to have the fields you are selecting in the used index. This way you will have a covering index, so the data will be read once only from the index
If you need many fields to be returned, you may first select the IDs using the query you already have, then send another query like this: SELECT * FROM Catalog WHERE id IN (list of IDs from first query) [In total, this may not be much faster, but try it to see if the difference is significant]