SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '25be189fa1be00ce49861473bca5781de952a4118b3a74a00d8f5b5705521947' 
  AND token = 'dbklFatQoXKhVtZPVUntXPEBYLEG9GLh7C2mgtgWP2s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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