# the two original arrays
bash-4.1$ array1=(a b c d)

bash-4.1$ array2=(a h c d l k)

# lookup array
bash-4.1$ declare -A array2rev

bash-4.1$ for i in "${!array2[@]}"; do array2rev["${array2[i]}"]="$i"; done

# checking elements in the lookup array
bash-4.1$ for i in "${array1[@]}"; do echo "element $i of first array is $([[ "${array2rev[$i]}" ]] || echo 'NOT ')present in the second array"; done
element a of first array is present in the second array
element b of first array is NOT present in the second array
element c of first array is present in the second array
element d of first array is present in the second array