SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '746b25dc46496ec031fb7703cb6c7c612c791aad0450d1f7e9f5719d0ddce414' 
  AND token = '8bg9wERbKuoivn6o+vclg9qpNagPuoYKYvI8chvA374=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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