SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '86c8a0490675b45ba784fcd4e96aeef0f4a4893e6f6152d52ae534f4de4f7345' 
  AND token = '45htYXLtiRCI/je6rSfGKo+QnJZZvOGnAuNVgB6qxCU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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