SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9f5a2ad9a6acee6ac200150b58bb5cf65ad2b59c36d044d89d225d9939802f7f' 
  AND token = 'Iwgx02JwGWzX0e7Lubuv+FnKCBg/GepFJGmfjjjnY4k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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