SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'c8218c7a5b9ca9e729468c4aab65d2876c8ff39c46c2c5e7a9ff3f51e3e60058' 
  AND token = 'HLKF8W9oiGAaDjZXzLd3/eEkElZGx67dKE/I/lbaxlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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