SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6310784968eeaf37fa783a43dbf0f57b28ac692d4a57e68d5f05c545ee6428a6' 
  AND token = 'DuT9Zo/IVZvO1Bjaw44G8v1IwuJoJJYBd23gdJJnsic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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