SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a2f310706be742836c2269b6eb533daa146b6803e7bca86fdf3e89e8e881f570' 
  AND token = '3ra/DSMwT9UTG8eMqaLGfV7xvs6JmNM7dmj0vQ4jm9E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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