SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78dd57d8ed7d6d8a9e07bb0762af102e12eb9c39627b7eec3b782dbc31f10dfa' 
  AND token = 'JSeYxrJ9Os17GYFw9ngWULmoGz2/XHx6jqPd3VGVGSU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00043

JSON explain

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