SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '898231324925217b797ef0ae26443758bc5b6c023c54e6b7146c9c7e5a01ad56' 
  AND token = 'UE8EVBqvUvJKbDwEgP5WRBLqvq1dUzV7j0KtNk8to3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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