SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd210f08bc04bb7e20440baa2299740497b012571ac56ae8f9b04a69be339a9eb' 
  AND token = '/XmCl9xKdN6rPTFwdwVhFwmQvcpTPbzfzV9Ck505L6g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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