SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '4773fb898e84dc35f2cfc7a299c8b9c34601764a5f31607aeb85a590ca559ec7' 
  AND token = 'HedWIu7wn6QiXkGwypAaq5sE/t3NCiZS21nIrtcs8s8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}