Although I'm Spanish, I can't recall for a word that accurately translates "lorekeeper", as the person who knows the wisdom and tradition of his people.
In celtic cultures, where the tradition is mainly oral, the bards ("bardos" in spanish) were the ones who maintained the ancient knowledges and passed it from one generation to another, mainly in the form of songs, or poems.
So, depending on the cultural heritage of your context (for example on the north of Spain), you could use the word "bardo" as a somewhat equivalent of lorekeeper. You can think that all bards are lorekeepers while not all lorekeepers are bards.
However you should take this with a grain of salt, as the use of the word "bardo" has evolved quite a lot with the past of time, and today is something perceived more like a minstrel than a lorekeeper, so... while the use of "bardo" would be ethimologically correct, maybe your audience don't understand it correctly.
a direct translation is:
for a game or a novel:
The Grand Mayan Lorekeeper
El Gran Guardián de la Sabiduría Maya
"Folclore" es un extranjerismo
"lorequiper" puede ser el siguiente
you can use a traduction note, it's common in science fiction or fantasy novels.