SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'fece47d4ae412448c6d4f78b5a9e7d1f02f4f75a01317b93f1d6459469efe894' 
  AND token = 'eP7mO+OtbklCFycVhclRYozzku/pDNk4sjK/8QPzicA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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