SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '72bfdbb2b24e76eeb441a9a5b97556082b6d705a38711524d568b099b8b5ee88' 
  AND token = 'MtCBeKf7DrDKtbS9LQMOvm1bhGturKGuIfG+kIvpNj8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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