SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '024f80a4a07db5b03c0605adef14952aff9976419472304297c9d7102dbc0577' 
  AND token = 'FtazPhsGHGkCiIvD+81ROi+6GNwY4BCeaSLVGce6BZA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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