Even though you didn't post table definitions in your question so I can't tell for sure what is missed, the following indexes will be beneficial  :


Index on table (user_id, created_at)
Index on users(id_str) or even users(id_str,screen_name,profile_image_url)
I guess you already have an index on table(id) 


UPDATE

Change WHERE :
from WHERE UNIX_TIMESTAMP(t.created_at) &gt; {$today}  to WHERE t.created_at &gt; FROM_UNIXTIME({$today}), this way optimizer will use index that includes create_at column more efficiently.

How can I improve this DB query? it takes too much time
I'm planning on building a built-in window seat against a wall that has two windows  with sills and an apron that extends from the wall about 3/4" to 1":



What's the best strategy for removing this extended part of the sill so that we can build flush against the wall?

Figure we have the following options:


Replace with new sill
Cut existing sill flush with wall
Build on top of or around existing protrusion


Doing #2 would clearly be the easiest but I'm concerned about any draftiness and sealing it back up right. I'd prefer not to do #3 as it would affect the height of the seat by a few inches.

Any suggestions are appreciated.

For reference, here are our renderings of the intended unit.  The gray part is a vent for the radiator behind:



