SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f5fdb8cbb35def5cb9b82a9868ea344f590a1c590caa9eec006458199b893db8' 
  AND token = 'sHXGHJfiQIC3h6OgZEsOJA7PPLSi239WubNb1EBh6Hw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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