SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6b8d24dfff9479dac5be676079a6147bcbb6172bce833c3b8248eed7425047e7' 
  AND token = 'YYkvgT5LfISmA3yB3JtprGFAd7LJ5qh+/S+CXkM254k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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