I formatted the question body to make this a bit more visible: the coordinates you said you got from map.getBounds() make up a box with zero area - it's effectively a point, as immediately pointed out by @user30184.

For that to match with &&, the geom in your map_locations would have to happen to be that exact same point, a line running through it, a polygon that covers that spot or a collection that includes one of those.

That ST_MakeBox2D() could cover 12.5%-25% of the surface of the globe in some cases:

ST_MakeBox2D(ST_Point(latitude, longitude), ST_Point(longitude, latitude) ) 

ST_Point() accepts lon/lat:

geometry ST_Point(float x, float y);
…
For geodetic coordinates, X is longitude and Y is latitude

So on the North Pole:

with cte as (select st_setsrid(ST_MakeBox2D(ST_Point(90,0), ST_Point(0,90)), 4326) AS geom ) select st_astext(geom), st_area(st_transform(geom,3857)) as area_in_3857, st_area(geom::geography(Polygon,4326)) as area_as_geography from cte; 

It still won't necessarily && with your geom, and if it does, I'm not sure that's really what you wanted to find.

I formatted the question body to make this a bit more visible: the coordinates you said you got from map.getBounds() make up a box with zero area - it's effectively a point, as immediately pointed out by @user30184.

For that to match with &&, the geom in your map_locations would have to happen to be that exact same point, a line (more or less) running through it, a polygon that covers that spot or a collection that includes one of those.

That ST_MakeBox2D() could cover 12.5%-25% of the surface of the globe in some cases:

ST_MakeBox2D(ST_Point(latitude, longitude), ST_Point(longitude, latitude) ) 

ST_Point() accepts lon/lat:

geometry ST_Point(float x, float y);
…
For geodetic coordinates, X is longitude and Y is latitude

So on the North Pole:

with cte as (select st_setsrid(ST_MakeBox2D(ST_Point(90,0), ST_Point(0,90)), 4326) AS geom ) select st_astext(geom), st_area(st_transform(geom,3857)) as area_in_3857, st_area(geom::geography(Polygon,4326)) as area_as_geography from cte; 

It still won't necessarily && with your geom, and if it does, I'm not sure that's really what you wanted to find.