SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '65c721c5970cb1367f613fc23a9f1c1607f0de25ffcda3fa65047dd8be378392' 
  AND token = '82tkL2+wqSJ2kECBVNnCqAyi+YAxOruV/ZKurlx8CC0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}