SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'a5557540ebf8f696bfdfd213cc75fed863adfe81b6735d965b87a52bd3166c70' 
  AND token = 'NSjod5ZZ6v+MNHXTXztnKT/WsxSzP4anIBIydbHHWAs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00093

JSON explain

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