SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '4872bddfce9db39fc495a5b66430ef5592acd16541c42ebfedf8ce8feffac787' 
  AND token = 'HYxMOKoA8xb2AFJwJSJJHY6XjuywtUzEH0vtVk6aCN4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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