SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5a100ab6a7b7e794261f579f567d9acdfff5695b9f863952536ed30585b8f4c' 
  AND token = '3FxdI7YtcXA2rxkMIBmfeFqvgxvavVKpIISPJasoOkM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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