field equal to OR between 2 fields?

[Jason McIver]

Hi, I have a record table that is expected to see past 500,000 in a year or 2.
Among the fields are these 3, 'start' (date) and 'end' (date) and 'type' (int).
I'd like to check if a date matches between the 'start' and 'end' fields, as it would be the easy way out for the rest of the application, but would matching to 'type' be much quicker? or no real difference?
I guess what I'm asking is, how much difference in speed or efficiency is there between these two queries:

SELECT * FROM `records` WHERE `type` = 1

and

SELECT * FROM `records` WHERE `start` <= '2010-06-01 14:50:20' AND `end` >= '2010-06-01 14:50:34'

Jason