SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f7a314c87dc637a53321f8328dc26ce908a31b579420a3b3cce8b1d6784b815' 
  AND token = 'lJAg37WSFP1emEi2MqDcuE6KyupNliKGGgWHjsqr18o=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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