SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b1ac9b53caa59020005593fa44cd13b2cbd0a4b34a12b291078b0a58f26994e5' 
  AND token = 'YlzYpOv5be/kxtqwYWuDsFuFw/AbPdyJ+vLnIS067v8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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