SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a4da70f0d362b10921c8662ffb97f13f55398bef1d60c14b16d70de6f46ea7d1' 
  AND token = '/4WQ6rfc2ErRPYHgZygiQv8vvWBKWiVc9+kmaJMO1AM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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