SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = 'cbb3f0ab14b8f0129047da9828c934d8d1030a66d7224ce7a63f836f45ec24b9' 
  AND token = 'BjkZQ9kUZNw9ogdOo5j7qj07U5+8Zg8jAVNx+jicKeg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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