SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fcdc4a43b7a145587ccbd674bb4aaf1d75efebdfbcecefc52bc6b3f2266d3ca' 
  AND token = 'sOLpvkKeWawyH2eQzwH7kEXEDHUWav8MNfS7Ipn8mUU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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