SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '328718f6ae71358b341863fc8dd4932928e5b038b9c0fc025d7ca472b37843df' 
  AND token = '9nkMCyPkotVvn6s0DrcIzBWIf4NinC/cSVg5GPsmvLQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00008

JSON explain

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