SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2fefaa73b029ccb455e1d9c31b1934cdbdbb71855f24ceb3a8ccc51c7c689ab7' 
  AND token = 'IVZqYsiAktYsYfgPgsvre0loqKvURrGue+VAaydM0rw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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