SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'be3080b07d5f8a7fd7254d596fd3faa07894051056bfd2dce9445e2cc572b085' 
  AND token = '3SQnsS73ntnt/XgwAdvtxtTcjKw7IAERaY/svZClXVI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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