SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e6018686c04433273a3323bcba9a21e93995e5328d9477f249d556bd99bfac06' 
  AND token = 'F07zyLY2A4Qs/pMpCRab0mjLhNkHbV+rwqGUx+eC9Gw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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