SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5b31baff20ea0d801da470758dff7baae56d122f3801f30efedd141c4d983ca1' 
  AND token = 'EuQG0GFaSikL0mI8pFJfLIel1aV+mfXCqxBzZ/dPp/w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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