SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd859f1b78910dc1c3e4e514e839f782c3786e68579d85de2802321fbad598bbc' 
  AND token = 'gbsyPBPe+xxTwbfHicorPEhfHgmCOFKkmxKvBdXOtCs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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