SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36dfbffe3bae5da5712813b9ede1d4d7d198c3ce79bcaabb9d5cf62738ba717a' 
  AND token = 'l2rlunLJ7gDjUDWpgMh5xcn5dXFmISKAyIoP85MD8dA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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