Our friend "Google Translator" did an horrible job with "caja de desayuno". Yes, María Renée is right, in Spain we say "fiambrera".
In Spain we usually call "merienda" to the whole meal and the most famous piece of food of this meal is the "bocadillo". Over time we got used to say "la hora del bocadillo" to refer to this meal time. It can be at 9-10 AM or at 17-18 PM.
Saludos a Texas!