SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'aebf736d2f3241251fa85dcdedf21f0f379e1274d81dccbca726daeb88b20826' 
  AND token = '4w5u7+HGghOQN/YZMHqRdck7Py3CBClvB1Ynu7ajJtU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00050

JSON explain

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