postgresql - How to find nearest line from point using PostGIS?

I have a table of Roads in PostGIS which geometry is "geometry(MultiLineString,4326)".

Its attribute are

gid osm_id name ref type oneway bridge maxspeed geom

Now i want to know the closest Road from latitude and longitude.

Also I want to set some distance from that Line/Road like 20m both side and if the point is within that distance then it should give the name of that line else not.