SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '03bcfe4a13ad83b7c16983f5f87d891286637b547fae8787f6adb515cef9ab85' 
  AND token = 'KYYz5upRjswWUxf9FDlDCynj32LahENvOtoUhUZmOS4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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