SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c0463f6ed71c3e7f2d8e3ea30b2fa19653b2b90c04f8d3b1f0712e8076a72fff' 
  AND token = 'FsuxU7BBiyV0QgCCHdpuwgWYbbhZ++AyxbFNDDJlsVc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00055

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}