SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '689bfc8828939b693a931862fd36fce575914f0fa584a53645ced3b0f0a6140f' 
  AND token = 'i6FewJ+ZFa2KMKgNEQe6n+OfKC8GcVJvYhsqYafV7hI=' 
  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"
    }
  }
}