SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '427ce3f74d35cf8a1bdfe32259eb9f3e5b5167dde1e1727045a8f9996cc667f8' 
  AND token = 'nBK+CPkLQJbZ6dRv1FXj836ghgR7FtAgxrWow6ckHuw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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