SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '8b40810c02aa9fcc0d5c210571c0837bd84067a85c736908887117c19b028d3f' 
  AND token = 'SE0mPxoDEZMbWuvlzSGXmjlKB9f0tMLuZ+mCNi1GSew=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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