SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36cba2cf96d496996dcc9fbaca7ed4105564a1ecf2ce5159989c4605782750c2' 
  AND token = 'U/oLc4rqXXHgXvwZF5YcCFj+pjF/Oywfim3G186wIro=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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