SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '36b053f79eb018d5e7ffce92e25036e9d7a4c1e15c81543959dacdcd3603a296' 
  AND token = 'nDocYGf1ZpkKuyAJBLA4/wXQz0VwJhoAS90PggfeMgk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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