SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1bf0b8391aa367137b2314bd86c7cf73fbfaaeccb07d16fa67ec3d751826ec4' 
  AND token = 'i6xf3UznCIVbDzixAePWoKk+NxzTuMnw29RPIJGjeZ0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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