SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c86dfc9a533431e77cbf7397cd96e8fff9916250247c5f3dced2a4ee1ed3d7f6' 
  AND token = 'QInOMB8hinI0hPVyZqOr7ny3O4OZPw7pKj1xuCEnoZU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}