SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6bdf1cf87963eb11d3dc03fd506ada599590c92cc8999c46ecee313a07b7f36d' 
  AND token = 'zPQ4odyB9IMlVDOeVsvlkm9T7kLO966fFYDWRd+/q/I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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