SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '5c088b5794ed1e688b13dd829b699095197707398c006e2aa2f11d2b023ffffa' 
  AND token = '09NbCfSiNts8RI5XgvleRTqa2bSyAtnO11XO2r04acI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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