I have never mined redstone with a wooden pickaxe before. How many seconds it takes to mine redstone with one?
You can't get redstone with a wooden pickaxe. The only way to get redstone from a redstone ore is to mine it with an iron or a diamond pickaxe, as stated on the wiki:
A single redstone ore will yield 4–5 redstone when mined with an iron or diamond pickaxe.
For the time needed to destroy the block if you were doing it with a wooden pickaxe, it would be 7,5 seconds. But then again, you wouldn't get any redstone from doing it.
You can see a comprehensive list of breakable blocks and time to break them here.
The data for Redstone is as follows:
The red background means the block will be destroyed without dropping any resources.
If you want to mine Redstone Ore, you will need a pickaxe (or other tool if using mods) of the
Redstone level or higher.
Redstone level means that you will need an Iron or Diamond Pickaxe.
*Technically, you can mine the block with a Wooden Pick, but you will not gain any Redstone Dust from it. The Ore will be destroyed and it will take some time.