SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0bbd458282d5256deb392d9ba9d393314643f6cc34b103e59b1d8922da11683d' 
  AND token = 'dx0DOwvki+xS2kmYaXEID9ik+xBUgVHAZd+EtXUs/WM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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