SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f7fe9273d7c307edb112eb49073315f471b1688760549be5b4122a10f5312743' 
  AND token = 'T3MIzxin9FtXjKs4MkTtgYFFJlMDXAcb2BmcX47yU20=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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