SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c473300e18b10f53de9e09eddf8b5e051ca53712790ac6fd4f5aa3e7f496e9f' 
  AND token = 'EE5EUcJ4oKqdWojbZEKYHiG7g/rBvvArdKuA62at6IM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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