SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'acfc8dfdb3a8751260a5e0b5fe1199e3b6eb6aeb688a8783a3fed8e36a5621ed' 
  AND token = 'YMkwmANIawCGkSTfXuGQtmx9zLqMzwx5n9lESc7Pkq0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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