SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '834ffed6f1653a05a0eacf9184797c67483707f172d7848af8b36fda7def280a' 
  AND token = 'NttHunphMjWAa6Txm06D21OkMwVpPIaus91megIBPrk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}