SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '517045af37477f5017885e82c5f1b6ef2625a80b63dd96d365ffd4eab262a9b6' 
  AND token = 'ZlyLkfV0QGr51jNOdD3XHVGnJJybGmpUIqVSxKW9Oec=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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