SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4e64d48460d5e3cf4c23eaa0a8a69e757986cc38606e1e1d9f2a735630a43f4c' 
  AND token = 'Y9vbFuTC2Y8DD+8KUEzBh9QyiPKWS+N/oJLKTiOpVow=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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