I want to send 1 bit for example : HIGH or LOW that all
If you are just looking to send a high or low signal to the receiver, there is no need to send a whole byte, you can just use an output of CPU 1 and connect it to an input of CPU 2. The differential driver keeps the noise down over the 5 m (or potentially much longer) line. You're not using it to send a serial signal, you're just using it as a line driver from a single bit of GPIO to another.
Over 5m you probably don't even need any biasing or termination -- here's a blog post about that.
The pair between the two driver chips is supposed to be twisted, of course, but again, at 5m it isn't going to matter. You can use any driver chips, pretty much, the ones shown here (75176) are the dominant pinout, with very many pin-compatible devices, and will work fine for you (if you have 5V). (Here's a Maxim Application Note about how to choose driver chips if you have any challenges such as long lines or high speeds: you have neither.)
In software terms, the output will be "instant". In hardware terms, it will probably be something faster than 100 ns, but it depends on a lot of things (mostly the exact driver chip, whether there is biasing, and the length and properties of the cable).