SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'efb702f13482afe5341c4c742841de396b80a3f96522e82592ad9b27b48c56db' 
  AND token = 'vEJZVuLRE+N0Bw2K2V5eOYDBxOF5xTPOM8JeqyzS+JA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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