SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '1b8279072ea4fa2540079df174d86f9f087ededa095347ae249b33a8d92024ab' 
  AND token = 'm203CGT2SX3hbgUkIpwdg32nIE1RUXOnoAxaKo+IbQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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