SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'da3104c6d21aaddca4baed2736c94a3ac4d287f1fb4a946e5a6aed3c22c37598' 
  AND token = 'lflShEqX0Pgw5sWpeKhUUblTb93aV112sQe70g+RsNQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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