Coxsackievirus A6 (CVA6) has emerged as the dominant etiological agent of hand, foot and mouth disease worldwide. At present, neither specific antivirals nor effective vaccines are available, creating an urgent need for rapid, low-cost in vitro diagnostics that can interrupt transmission. This study developed an electrochemical biosensor based on a "screening-validation" strategy. It utilizes a MoS2/MWCNT/AgNPs three-dimensional highly conductive network as the substrate, tightly anchored with p(NIPAm-co-SBMA) microgel to form a "protective-conductive" synergistic interface. The capture probe is immobilized via AgS bonds, achieving three integrated functions: signal amplification, anti-contamination, and specific recognition. The detection process occurs in two stages: First, the target nucleic acid sequence generates steric hindrance signals through direct hybridization, enabling rapid initial screening within the 1 fM-100 pM range; For significant initial responses, the CbAgo protein system is introduced to specifically cleave target PCR products under guide DNA direction. The resulting short-chain products trigger secondary cleavage of surface probes on the electrode, enabling sequence-specific validation. This reduces the detection limit to 26.5 aM, with a linear range spanning 100 aM-10 pM. This layered strategy significantly enhances detection specificity and reliability, establishing a new paradigm for precise viral nucleic acid detection.