SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '482cfe337dfc70b0c8c50b352031961f19f7b069c9528d2f21e24e0653a8c538' 
  AND token = 'rbhn8uQd5PsB39aLRYxT0SOtijZdMtdmF8GawpKYRZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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