SELECT 
  1 
FROM 
  cscart_multi_declock_keys 
WHERE 
  key_id = '86e3dfe232edd544fba008f7ebb6fced00892d097ac3aa3c4d52c6de0baa37b9' 
  AND token = 'CHPavP7K+R0uqo8ssRDEjAjKKHcJFZxFEzktipweGzg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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