SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5ff79eb28c9fdeab40d121b588a952d6f9cf169d9b796f02d4ba93a7f7fe927f' 
  AND token = 'mZYyRll5btCt4aNJQyQvJYv2nzQNpuUA0NRXDMqStlc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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