The Mayans didn't have coins, no new world civilization did. The Aztecs used cacao beans and copper ingots but they would certainly not be able to be recognized like coins.

Here is a question that asked and answered before about the currency of the Aztecs

The Maya never minted coins, so I'm not sure what you heard about Maya coins making it all the way up to the SW. You may have confused this for the trade in cacao seeds (often used as a form of currency in Mesoamerica). For cacao seeds we do have evidence (from the site of Pueblo Bonito in Chaco Canyon, NM) that they were traded (albeit in a probably limited amount) into the U.S. Southwest. That said, there is no evidence that this represents trade directly with the Maya since there are sources of cacao much closer to the U.S. Southwest, including the central Pacific and Gulf coasts of Mexico.

There are other indicators of exchange between Mesoamerica and the U.S. Southwest, including copper bells (produced probably in Western Mexico), marine shell (from the Sea of Cortez), and most probably some transmission of religious concepts and iconography (including something like the "feathered serpent" concept, seen as a "horned serpent" on these two Salado Polychrome vessels and this Ramos Polychrome jar, from southern Arizona/New Mexico and northern Chihuahua, respectively).

That said, there is very little evidence of direct trade with Maya people specifically. For instance, there are no examples of Maya hieroglyphic writing in the U.S. Southwest, or kinds of material culture (such as artifacts) exclusive to the Maya. On the whole, it seems like (based on the aforementioned evidence of marine shell, copper, and a few other reasons) Western Mexico interacted with the U.S. Southwest much more strongly than any of the societies living along the Gulf. Perhaps this in part is because of the geography of the Texas plains insulating the SW from the Gulf, but that is straying too far towards speculation so I won't say more.

If you are interested in trade and travel in the Americas prior to European colonization, we do have an entire section of the FAQ devoted to the topic. I would recommend the question about trade along the Pacific coast in particular since several authors contributed to answering it in extensive detail.