SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dac3480bdebdebd1369ce5d8bc4963b718b3b60a810c60973e122e7300f4882c' 
  AND token = 'RvpVLJmyQB4nz5Y/0/P0d9k4E8xmA8EkwRoEZiJDVgQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00051

JSON explain

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