SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '71a21921654ff0dad574c536a4d26004b3c35605dadf2f47c82b260d1590d360' 
  AND token = '2ZVEW/vJSzCS6rb5brRexYxKgh4dWNPKgTuB5KOWqJg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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