Why don't the single serve coffee cream cups need to be refrigerated?
Those single serving 'creamers' have been manufactured using Ultra High Temperature (UHT) processing. According to wikipedia (the most reliable information source in the multiverse!), milk treated by UHT has an unopened shelf life of 6 to 9 months.  

The reason there is no 'best before' date is that they are purchased in bulk by the merchant, the container for a bunch of them (which the retail buyer will rarely see) would have the best before date on it.