select count(*) status these days

I'm about to launch an in house 'Aplpha' stage project. One of the marketing driven outputs on the page is filled by a:

SELECT
  COUNT(*)
WHERE
  date_field IS NOT NULL AND
  date_field > :todays_date;

Last I heard, this kind of query is kind of slow on Postgres in particular, (Love postgres otherwise). Is this still
true? 

Is there any architectural way to speed it up? I'd actually like to run it every 2-60 seconds to update a counter on a
pagefor the marketing guy, (which for once, is me :-) 

Dennis Gearon

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