SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7649b8f67e84242575083f747344543dfb9ecfd5726183c8d9e906e95c02467f' 
  AND token = '4KcBhYN+Cy1ax7ZBNn9JLm46BQvJqMAyCMAcBUzwj/M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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