SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3dab875a4131a3f388d618e94246afe5b431404c2b99c3515db79b239807dfda' 
  AND token = 'ZD3G8wp1a1ow4Ao5VW/6Ltp7TldSC6nWLCQyrt5GhDI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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