SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6e13bcb05ad04deb1dbefd36b29a52c077fa722bdd64d486a47f8fe4c778152d' 
  AND token = 'U6aMRF7b25sykeT5NPgZu46krOv2SS/V9Xze/XEqdRA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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