SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = '0878b1a2ed8b8fc248d95de3aa692f688e5bbba80f3cdcab483dad82409c0fc1' 
  AND token = 'wIdVTgsoczEPOtFunPajcLU73dCQRKlhgSY9AG1aw14=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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