Get if player is at certain location, then set scoreboard (1.15)
if entity @s checks if the entity that is yourself exists, which is (almost) always true.
positioned executes a command at another position.
In general, looking at the wiki helps, it would have told you that /execute positioned is a completely separate branch of /execute.
What you want is positioned <coordinates> if entity @s[distance=..1] (or any other radius). This checks at that position if there's this entity in a radius of 1. And you don't even need at @s.