SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1b7364789c1898d32978828a7d81d9724eec6a4266c48530aaac8287e95fb1a4' 
  AND token = '8MQ/q+OgIvxCjkLRKOvTNfx/Bph1xhluFuAtl713PGY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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