Cantina is technically a new band, and A Sea of Keys is its debut release. But it is also a veteran group with years of history, essentially a slightly expanded and rebranded version of I Love Math, at one time practically the house band at the Barley House. There is even more history that comes along with these 15 songs. The friendship and partnership between singer-songwriter and guitarist John Dufilho and bassist Jason Garner that exists at the heart of Cantina—and I Love Math and the Deathray Davies, and San Antonio’s Big Drag before that—is decades old. And the boldface names that appear in its members’ respective résumés (Old 97’s, The Apples in Stereo, The Polyphonic Spree, Dropkick Murphys) are not exactly unknown entities. Given all of that, it is not at all surprising that A Sea of Keys is such a comfortable listen, one of those records that feels familiar 10 seconds in. The mostly acoustic back-porch pop of I Love Math is filled out with a tinge of banjo from new member Marcus Hollar. But the charm of Dufilho’s playful songs, delivered like a man with a hangover singing a lullaby to his baby, remains.