[Al Watsky]

The clip Big Tony posted is in E. Most of the lines Cropper is playing are in E mixolydian the mode based on the key of A major. The Mixolydian mode is used for dominant 7th chords.
His lines are based on A major at the interval of a 6th, against the E7 chord.
If the tune is actually in Eb the lines are Ab based.
I like the steps the horns are doin' that takes it over the top. Showmanship.