SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'addcfa0b66dcdd2d58357d30f741f0f481e9005e41d6911776660e087d5f84d3' 
  AND token = 'KmOGfgGLsoLQoUxMRbwfAB6bSJcG78sbUuH87rhDcOA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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