SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7e13cd172e230cc0682aa8e4dd1f96955dd28c1c541ae32cb3e4c4ff9f9a91f8' 
  AND token = 'uvXB/gjEvikZbQRH9sBDrMQCdEV5n2HPINnZKteUwHA=' 
  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"
    }
  }
}