SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'acc591a50e1a32e2accfc715c6a9bb6accdd49073ff965f5dd576d36f692db00' 
  AND token = 'DqjRW6ykMPPRvTG5aeO5dl3+hshnLJDYDQTjZ5gPads=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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