SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '5bc3698e36c13dfd8449f160a139bdef5a736302890fc341dd23dd17d9fb4c64' 
  AND token = 'BGpux7TPEvB+QD/W1lY63kntEshviLTtKcpRVBWWWFA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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