SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dc93a04e24689c7e6d491b48c49ad68f4fffba0494b9eb00965bd5a5ad6dc6c9' 
  AND token = 'O9cSxTK2aUeXpdgglBhZfLocMznjC2EeMrqi0xSo2Nk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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