SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '76c31bdb377364a9834398763040807a358dc121808f2111fa70542016d7fe24' 
  AND token = 'YcGjaaBWrHIJdC3Ofr0JHsFBypW5WIQgxqQQmXdFXd8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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