SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2771e72205c6fc76b3d7a015be292125bdcb86f8e535966a2d4ffd32a4e76e5b' 
  AND token = 'j9/xvfqTxvVn+1E1MvFdKchGWQunSMYi8KsQYiutVcs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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