SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '88f765e73376c72814b4c330933a4526f041a6b7b7dc6dcccd56eb395fbc76b6' 
  AND token = 'wG+wz2QNhKsCDCYzkTajKfJMaTQhxVbqCsrKdvnjt3s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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