SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'deb13dc85d99de44bbac09a7e06923e9168e81a59c67999252115aebb48ff013' 
  AND token = 'tVUFiRvUchICn+o8s681qAIJDfHPlGx4101alH8VrdE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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