SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4c0f252c477a0dc4e626b6f0c46dcf05db1cfad4edf3b63129f410b431e838f8' 
  AND token = 'avf3sjMfJC1BoeZzAyG5XUJuf+YHh98eyH7GiPyjH/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00061

JSON explain

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