SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0477876a7dfca854f825284269f285c2dece2b61035a3090b91bb31697001632' 
  AND token = 'Y142rizQVVR5hmaDAq47MVxASBBqqOjnqZkNM1jcTy4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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