SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '9df9e1156515e9917af71865730de426dbe0432f848e64dc1f691022866ac2d9' 
  AND token = 'GOI7OVHRB4xLzdOQ4WF8nlU89aS8YG6JZJUO9H954eM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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