SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '420d075237753509b24ae92a6b5f2cba4ec815d13634a7dc8f532cc45443690d' 
  AND token = 'ZPOlhXyhZDlK9u9MhhdxIuR/2JSPfO898g3LpT1QGYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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