Night Vigilance

He is on the corner, as always, at the same hour, in the the same place, him, young, but not so young as to be immobile like a gargoyle. A guardian of the night.
He is waiting for something under the streetlight (I'm not 100% sure here, but I think farola?). (bajo la luz del foco de la calle)
He is looking at the ground, staring at it, as if a flower were going to bloom
although he would prefer a coin, to save the night (not sure what you want to say here, maybe he would prefer the money he needs to save the night).
Or Maybe (I would say Perhaps) he is waiting for an order from his boss, or maybe he is just waiting for the night to be over to add it to the count.
I think he is just hoping (esperando que) that a stray bullet doesn't hit him or maybe that he can finally finish his night vigilance.

As promised in the comments on my original correction, here is a version rewritten into my own words.  I've included a few notes about the parts that either weren't, or still aren't, clear.

The Night Watchman (I didn't understand this from the original story, but after reading the comments, it makes more sense as "guardia nocturna" could be either night watch, which is a thing, or a night watchman, which is a person.  The person makes more sense in the context of the story).

He is always in the same place on the corner of the street at the same time.  He is inexperienced, (The word young also was not clear to me in the original story since young is almost exclusively used to mean «joven», but I'm guessing that you meant inexperienced {«inexperto», «verde})

but not so inexperienced as to stay in the same place like an immobile gargoyle - a guardian of the night.  (This part about the gargoyle was confusing, but after thinking about it for a bit, I believe I've captured the right idea.)

However tonight, he is just standing there waiting for something under the streetlight.  He is staring at the ground as if he were waiting for a flower to bloom, but he'd rather find .... (I'm still not sure what you wanted to say here)

Perhaps he is waiting for orders from his boss, or maybe he's just waiting for the night to end so he can add it to his long list of seemingly endless nights. (At first "to add it to the count" didn't make sense to me because I wasn't following the story, but now that I understand it better, I've reworded it accordingly.)

I think he's just hoping a stray bullet doesn't hit him, or maybe he is, so he can be done with his night watch once and for all.  (Notice here that I changed it from "can finally finish ...." to "can be done with ... once and for all".  There is an important difference here as the first one implies he is done with it only for tonight, while the second implies he's done with it forever, which would be the case if he died from a stray bullet.

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I hope this helps!