SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b34b389c1a064b8633333ba39de03511d12a25f5ed0c735e71a7fc52ee54b96f' 
  AND token = 'GXKvyKop8rD+lcqnyxrGrNpkk7ddNYidZDW9wfBdxK4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00031

JSON explain

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