Fusion table API, INSERT query, bad request - sql

Question

I have a fusion table with fields: username, description,latitude,longitud,geolocation. I am trying to create a new row with information via the google API. I triple checked that the fusion table is open, the tableid and the apikey are correct, and I have the fusiontable API enabled with 0% of the quota. I think the wrong request must be because some coma or quotation mark but to be honest it completely escapes me. I have tried different combinations and cannot find the mistake. Below error that I get, the code that use in php to generate the link and the link itself. Any idea would be greatly appreciated.
Thank you
link returns:
{
"error": {
"errors": [
{
"domain": "usageLimits",
"reason": "keyInvalid",
"message": "Bad Request"
}
],
"code": 400,
"message": "Bad Request"
}
}
Php Code:
$apikey = "AIzaSyB4BMlrZIlJB-Apo8t_dO9K18uL8O2s5TA";
$tableid = "1X0rFoG7Tt2Ocm2rE39wPuamZCrFiS4D32Odgbh03";
$username="webuser";
$description="nujkn";
$latitude="78";
$longitud="110";
$geolocation="98.8789, 150.1111";
$link = "https://www.googleapis.com/fusiontables/v1/query?sql=INSERT+INTO+".$tableid."+(username,description,latitude,longitud,geolocation)+VALUES+('".$username."','".$description."','".$latitude."','".$longitud."','".$geolocation."')&key={".$apikey."}";
Link generated: https://www.googleapis.com/fusiontables/v1/query?sql=INSERT+INTO+1X0rFoG7Tt2Ocm2rE39wPuamZCrFiS4D32Odgbh03+(username,description,latitude,longitud,geolocation)+VALUES+('webuser','nujkn','78','110','98.8789')&key={AIzaSyB4BMlrZIlJB-Apo8t_dO9K18uL8O2s5TA}
which in browser looks like: https://www.googleapis.com/fusiontables/v1/query?sql=INSERT+INTO+1X0rFoG7Tt2Ocm2rE39wPuamZCrFiS4D32Odgbh03+(username,description,latitude,longitud,geolocation)+VALUES+(%27webuser%27,%27nujkn%27,%2778%27,%27110%27,%2798.8789%27)&key={AIzaSyB4BMlrZIlJB-Apo8t_dO9K18uL8O2s5TA}