SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '53584163887057e014282462793b3ca78ecfe4d7f758045288668804b493be60' 
  AND token = 'VgGuuTEJMTGqEoJx+z7YSqlvfP+p8F12P4cny9L7uCg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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