If you haven’t shuffled your feet to the soulful grooves of Booker T and the MG’s “Green Onions,” a 1962 No. 1 hit, you haven’t lived. But there’s still time: The instrumental band – with Booker T. on keyboards, Donald “Duck” Dunn on bass, Steve Cropper on guitar and Anton Fig on drums – performs at the B.B. King Blues Club (243 W. 42nd St., at Eighth Avenue; [212] 997-4144) tonight at 7:30 and 10 p.m. Tickets are $46. Known as the house band for Stax Records (and if you go to Soulsville USA, the Stax Records museum in Memphis, you can ogle the hitmaker’s original instruments), the Rock ‘n’ Roll Hall of Fame act created the magic for dozens of Stax artists, such as Otis Redding, Sam and Dave and Wilson Pickett. Not enough? Cropper and Dunn were members of the Blues Brothers band.