SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3b29ce62322cc67502d30677cc7d8ee9d3abbd89ec7bd246c7f210c574176267' 
  AND token = 'fzP58YZqpgomFzniF8YpOzL6jNjAZlPXyqbWMpH/s+s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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