SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '624c0abe217db3827bdf3155c31b3f3d4014dc1c2a30b82134c780058312ad4c' 
  AND token = 'IRYVq/7sAvbrR6zZ1mva0lApBWd8WCB70CnlyXKMms8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00017

JSON explain

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