SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '45406631900d3f99b30032db80a14c205680e7dcbd274bef5555af7303fdeabe' 
  AND token = 'DB7iSjuRvsBGN6uARAvElu33EAJf2tYHlz+FRUmB86Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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