SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '2161c4e1f647e77bfa48a5b995513866d384c8bec5072ce7a93d83ba5bcda096' 
  AND token = 'qx7xYhSnhdd5IODymK2+wWHA6rWgJ2jwweX7/U0DaWY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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