SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd959388e7c4a64becb8bdfc7fb61bcf1ee4f74f7ad012786fc70dd7e58092f67' 
  AND token = 'jIwZQMHl1OpoGJ/Q4gZdm/qJwncg0aBIzHbV+ZqUGo0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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