SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '710bf6103724ceb69969ab0cf0dd71b7dea3aed33b20e772ae9a4c926a604293' 
  AND token = 'TjKWhQTn26JvYugDPGIOZ4Oh5rWxhqgwsvdNbBezsZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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