SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8789df307f8841e2c8d4d0b73b18141b84753ef087124b99bd92a9f8ed901743' 
  AND token = 'SGZiuzuQ/ZuNKBnlVNK9rQEvawtEYNPd3lIyxBHKo8Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}