SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '63cf18e6d211b8925fa7a882f5c4700a7c973d5f25b949288dff02af15435492' 
  AND token = 'jNomigVH1xY+UPWLakJDw0hDqQHZ6uVd6f5+hASeqpU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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