VEP does not need every column of the VCF format, only chr, pos, ref and alt. Those values should be straightforward to extract from a SNP entry.

you could filter it with vcftools

vcftools --vcf $vcf --positions SNP_list.txt --recode --out $out

or

vcftools --vcf $vcf --chr $chr --from-bp $start --to-bp $end --recode --out $out

The advantage of that is that it will also work with gzvcf or for multiple SNPs, but honestly, it's probably just as easy to extract using cat | grep in a vcf as mentioned above

bcftools view will do this quickly and easily.