import json
import geojson
from shapely.geometry import shape

o = {
   "coordinates": [[[23.314208, 37.768469], [24.039306, 37.768469], [24.039306, 38.214372], [23.314208, 38.214372], [23.314208, 37.768469]]], 
   "type": "Polygon"
}

s = json.dumps(o)

# Convert to geojson.geometry.Polygon
g1 = geojson.loads(s)

# Feed to shape() to convert to shapely.geometry.polygon.Polygon
# This will invoke its __geo_interface__ (https://gist.github.com/sgillies/2217756)
g2 = shape(g1)

# Now it's very easy to get a WKT/WKB representation
g2.wkt
g2.wkb