@vakitiv welcome to the forum.
It's not the current time but the last modified date/time of the note you are viewing. Admittedly for a new note that is the current date / time 
Anyway, this can be removed using custom css.
In userchrome.css add:
.updated-time-label {
/* removes the modified date */
display: none;
}
If you want to make even more space by removing the spell checker button and the alarm button as well, change the above to:
.updated-time-label,
a[title="Spell checker"],
a[title="Set alarm"] {
/* removes the modified date as well as the spell-checker and alarm buttons */
display: none;
}
If you are not familiar with custom css in Joplin see this wiki page.