Unfortunately, you cannot. (at least, until they fix it, which they probably will, because lots of people are compalining about it.)

Setting the SkipIntroVideo = 1 does not actually shorten the load time. Nor does removing the movie file from the root install directory.

You who answer to the contrary (@FallenAngelEyes & @Oak), I challenge you to actually get out a stopwatch and test it. Results below.

**Movie on:** 20.4 seconds

**SkipIntroVideo Set:** 19.95 seconds

**Movie File Deleted:** 20.4 seconds

**File deleted and SkipIntroVideo Set**: 20.1 seconds


Test procedure used:

 1. Click the DirectX 10 & 11 launch option. *Start Time*
    
 2. Click the mouse repeatedly
    
 3. *Stop Time* when the ESRB Notice is seen.

p.s.
+1 to bwarner's original comment about the load time not improving.

p.s.s.
Oddly Civ 5 actually has lots of lua files in its install directory. Lua is an interpreted language and so you could change these files and see the results the next time you run the game. But I don't think these lua files control the intro movie or the game startup because of their location under "assets." It is a possibility, but unfortunately there are a lot of these. It would take hours to get a definite answer by reading through them.