SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f1ccff741e660746029aac4d74ca175f4f179e8263b08758e81e0e69ba24be91' 
  AND token = 'K/ZU3XB25fZ5vuiDmGIZ1ZOlw4YpUr1gWsYTb37Jx5g=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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