SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '785e4c013bf83126cfcd6620d11ed982407aca0ef499d88caf9042a7510a0cef' 
  AND token = 'Eg/glZqfyy8xl3zcuHUQGeotFnZhRL998TeI/Hx6ye0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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