SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '02b3b5ea5cf5e111660711a5cb27ac2ee60927821673d9d69ba273e7476f2cfc' 
  AND token = 'hUkzS8W3sOXoKbLwywYPHkDMcDzKgEvvHqNLNG2/GX8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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