SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9cbcd65f58e5d90a9f8fa756c61957f4705eaae63edbfb68b335282a9024b416' 
  AND token = 'QGEGhLvCZM5OKa7dN5QJm8hnN5+orf+IqBGLEMzoNYs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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