How to create a scrolling texture that only scrolls over a certain area of texture

I currently have a frag and vertex shader that allows me to add a scrolling texture over the original texture, however I want to make it so it only scrolls over a certain area of the texture. I have figured out how to shrink the scrolling texture’s box, but the smaller scrolling texture just ends up scrolling through the whole texture still.

Vertex Shader

#version 150

#moj_import <fog.glsl>

in vec3 Position;
in vec4 Color;
in vec2 UV0;

uniform mat4 ModelViewMat;
uniform mat4 ProjMat;
uniform mat4 TextureMat;
uniform int FogShape;

out float vertexDistance;
out vec4 vertexColor;
out vec2 texCoord0;

void main() {
    gl_Position = ProjMat * ModelViewMat * vec4(Position, 1.0);

    vertexDistance = fog_distance(ModelViewMat, Position, FogShape);
    vertexColor = Color;
    texCoord0 = (TextureMat * vec4(UV0, 0.0, 1.0)).xy;
}

fragment shader

#version 150

#moj_import <fog.glsl>

uniform sampler2D Sampler0;

uniform vec4 ColorModulator;
uniform float FogStart;
uniform float FogEnd;

in float vertexDistance;
in vec4 vertexColor;
in vec2 texCoord0;

out vec4 fragColor;

void main() {

    vec2 uvMin = vec2(12.0/128.0, 54.0/128.0);
    vec2 uvMax = vec2(19/128.0, 65/128.0);

    if (texCoord0.x < uvMin.x || texCoord0.x > uvMax.x || texCoord0.y < uvMin.y || texCoord0.y > uvMax.y) {
        discard;
    }

    vec4 color = texture(Sampler0, texCoord0) * vertexColor * ColorModulator;
    if (color.a < 0.1) {
        discard;
    }
    fragColor = color * linear_fog_fade(vertexDistance, FogStart, FogEnd);


}