SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'ae2a5689973aed6c289d888fa310fee7c157a23c7c24c14dc1a2811bd31790ee' 
  AND token = 'axt3fMhiH6EgSHFQ3OPDqlYe5QIb0YHLdxlTL4mjSgs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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