SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f08edaf74062b57f576f90c72d55d8e5c6649ed774d359a0d36fa40028e25ef' 
  AND token = 'RnQg5PcUMRzp13uh9Yu5Pk9HIMp2uPUfZDKazRtaz1s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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