optimize log lookup

src/main/java/de/diddiz/LogBlock/QueryParams.java

@@ -122,6 +122,14 @@ public final class QueryParams implements Cloneable {
         }
 
         String from = "FROM `" + getTable() + "-blocks` ";
+
+        // heuristics - for a small radius using coords index is much faster, but mysql sometimes does not use it
+        if ((loc != null && radius <= 500) || (sel != null && sel.getSizeX() <= 1000)) {
+            if (since < 0 || since > 11000) {
+                from += "USE INDEX (coords) ";
+            }
+        }
+
         if (needPlayer || players.size() > 0) {
             from += "INNER JOIN `lb-players` USING (playerid) ";
         }