SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '557456fc336b2dde8e504e730d754cb263e91b5c74f22711a09e04eb69ee23b3' 
  AND token = 'bMtEpcZ0YXJk/Gquy+WaKZ8znlI4AhHPmzTkTcAUCtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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