SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '548bb2b375c9bdbdbbd776ae42e207ca1d85a503ef9964e95199f58d7f7cf1cb' 
  AND token = 'PrLv+IjU4bDHQK4APWLOmb+eLUaoaKTApdf+tv31vnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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