Get user object from token string in DRF?

from rest_framework.authtoken.models import Token
user = Token.objects.get(key='token string').user

Here is The default authorization token model:

@python_2_unicode_compatible
class Token(models.Model):
    """
    The default authorization token model.
    """
    key = models.CharField(_("Key"), max_length=40, primary_key=True)
    user = models.OneToOneField(
        settings.AUTH_USER_MODEL, related_name='auth_token',
        on_delete=models.CASCADE, verbose_name=_("User")
    )
    created = models.DateTimeField(_("Created"), auto_now_add=True)

    class Meta:
        # Work around for a bug in Django:
        # https://code.djangoproject.com/ticket/19422
        #
        # Also see corresponding ticket:
        # https://github.com/encode/django-rest-framework/issues/705
        abstract = 'rest_framework.authtoken' not in settings.INSTALLED_APPS
        verbose_name = _("Token")
        verbose_name_plural = _("Tokens")

    def save(self, *args, **kwargs):
        if not self.key:
            self.key = self.generate_key()
        return super(Token, self).save(*args, **kwargs)

    def generate_key(self):
        return binascii.hexlify(os.urandom(20)).decode()

    def __str__(self):
        return self.key

As you can see this model has OneOnOne relations with the User model.

So if you want to get the User than mapped to specific Token:

from rest_framework.authtoken.models import Token

try:
    Token.objects.get(key="token").user
except Token.DoesNotExist:
    pass

For more information see Authentication documents

If you invoke the user object directly from the Token class, as presented in @aliva's solution, you will get a raw partial Django User with just the fields living in the database. If you need to get the real user object, with e.g. its computed properties, you can do this:

from rest_framework.authtoken.models import Token

user_id = Token.objects.get(key=request.auth.key).user_id
user = User.objects.get(id=user_id)