SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f6834838a7be6da57eab8ea8d9cadbc3224ffa3f5aabfd2370114a4328eede4f' 
  AND token = 'cGQkIngDiVmezTrswYbdl0pbrhXbPnMfLTzaWXGnHK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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