SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd5c568477a63cbbc5577903196da1e79ac7a8a8d110647153d6fd89757d904ee' 
  AND token = 'pCF4A68XCce7egZwsazys0ikbx19fYVGffm+cK8uIrI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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