This is a nice, easygoing bit of flash fiction. You've noted that it was written for the Flash Fiction Contest, the date, and the word count, but I wish you'd included a link to the contest so I could remind myself as to the word count requirement and read the prompt (or you could include those in your notes or a drop note at the end of the story).

Regardless, this flash story is complete, without incuding dialogue or direct action between characters. Everything the reader knows is related by the narrator. This makes it easy for the reader to imagine and relate to the main character, and it also feeds that angst he's feeling to the reader, since we don't know the right answer, either. We only know his perception of how their date went. I like this POV choice for a story like this to keep the reader guessing right along with the narrator.

The only point I had difficulty with was confusion about what actually happens at the end. The main content of the story seems to be his justification that he should take the key to her–he's talking himself into it and then out of it. It seems he's pretty sure she left the key behind as an invitation for him to come to her place to continue their evening. His conundrum is that he doesn't know what she meant to do, so he doesn't know what he should do. It's obvious, though, what he wants to do. My confusion comes at the very end when he leaves off with "–she just wasn't ready for more." This makes me believe he's decided her leaving the key was an accident and he shouldn't return it to her tonight. But that line is immediately followed by, "Acknowledging that, he turned around toward the door." To me, turning towards the door means he's about to do the opposite, do what he really wants to do, which is to take the key to her in hopes of extending their evening together. I don't know if turning towards the door is just a line than needs to be rewritten–that you mean for him to let go of the night and not return the key, or if the opposite is true. Some clarity here would be helpful, since it's what the whole story is riding on.

Congratulations on completing a 24-hour turn-around flash fiction story. I think you did a great job with including the bolded words (part of the prompts, I'm assuming)–they don't seem forced or odd. I really wish I knew what his date expected of him, and I wonder if you know, yourself? Thanks for a great reviewing experience, for sharing your craft with me and WDC for NINETEEN YEARS, and Happy WDC Anniversary! --And good luck with the Daily Flash Fiction Contest! Write on!