Name 'Key' not defined Lambda function to access DynamoDB

You need to import the Key function, like so:

from boto3.dynamodb.conditions import Key

Without importing it second time, u can address it like: boto3.dynamodb.conditions.Key

def getAssetExistance(asset):
dynamoTable = dynamo.Table('Assets')
response    = dynamoTable.query(KeyConditionExpression= boto3.dynamodb.conditions.Key('userID').eq(asset))

return bool(response)