SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2921a5aaa7e4e23c9c3b72d0ef01eac7229266a4969d5d52d80fbe1541f8a95d' 
  AND token = '/geilKpyRcjS/zJGxF4Uaw0YWOlxhB1p+ocrk8YfJBI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00045

JSON explain

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