SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '81fe66b404534c995329c30c891ce97d6d72cbf1c2556ab756066eeb9887cf7c' 
  AND token = 'BPp/X3KtPVz8oAT6axfmKPwQCu+XQ2fUOARKjG1OKSk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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