SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ac012577f9e78545999751d6bf3a1a7f808263e67ee77fdef49460098b28334f' 
  AND token = 'PBoGKlEZ9diX3H7qoPzgDWIfxhvUXgWiOVLGIAhXCH4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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