SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f14dd02814fc8fa44be4d5949a31f36b915a679ec580902cbf6d661fea6e909' 
  AND token = '31Cn/sqAdgS+AOtfVpmWcXLFhcaNHNGloq0uTE3mvWI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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