SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '566a0fe4e02537cec544e51259ca89bd53d7f1e03a2610f39fdc76865837db9c' 
  AND token = 'iElKpwdeCTVtjHmtRLAhQD7zieqUkWH0s0St7slhMbs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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