People have mentioned using manual focus to speed things up. And while that can certainly help, it doesn't cover the issue fully.
You camera (I believe) has three focus modes, One Shot, AI Servo and AI Focus. In One shot mode (and in AI Focus, I think) the camera won't open the shutter until the AF has been confirmed. How quickly the AF reaches it's target and stops, depends on many factors including the lens, the camera's auto focus abilities, the light levels and the situation in which you are in.
So even if you are already focused on or close to your subject, if the shutter release button is also the auto focus 'on' button, then there will be some amount of delay (over and above the base shutter lag).
However, if you use AI Servo mode, the camera does not wait for AF confirmation. So in this mode, the total shutter lag is going to be shorter/faster. Of course, this also means that your chances of getting an OOF image are higher.
What I have been doing for many years, is using the technique of 'back button focus'. Your camera likely has an 'AF-ON' button on the back, and older cameras would allow the user to set AF to the * button. Either way, I also remove AF from the shutter button...so the camera only focuses when I press the rear button with my thumb. So when the rear button is not depressed, the camera acts like it's in manual focus mode and (I would think) has a slightly faster shutter lag.