SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '18d8a366536631c9f72940b08146d2110837c31421fb225cc6b3f45df3b83564' 
  AND token = '/Klh3fiLr7wIUtXVxNc6tCyhQFZVxsKvTP1r7ZaQozI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}