Thanks for the help.
I do have a column called productId and I had been using:
WHERE productID = 'AB1234' OR productID = 'AB2234' OR productID = 'AB3234'
I didn't know that you could use alphanumeric characters in BETWEEN
I've changed to:
WHERE productID BETWEEN 'AB1234' AND 'AB4567'
And this has shaved a great deal off the query time.