SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3bcc1e4acbcfc4478bf6a3746497eebba615178820db81ada3477f4cdfeea3db' 
  AND token = 'Rdt77hgwED8TIYPR9+HmYXKv7OWPiflTvAwp9rQ7Njs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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