You would use AnimationState.time
It can be larger than the length of the animation, so to get the value with this, you would need to modulo with the animation clip length.
float time = AnimationStatecurrentState.time % AnimationcurrentState.clip.length;
You can also use Normalized Time, but you would have to mulitply the value by the length instead of the animation (AnimationClip.Length)
float time = AnimationStatecurrentState.normalizedTime * AnimationcurrentState.clip.length;