SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3d2dbf198ea57bdce36255cc1a85d9ac986537aeb21472f644279c89cf3a4877' 
  AND token = 'cYnyUATOWj4MwIAP4hD0oWyGjqKu/TBdpafR3QJ3aH8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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