SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad9a25c3d48822a33b334d76cdca8a2f87c0f9e4c4a3a36f09e32cef42b26144' 
  AND token = 'Jrvzp/6gf87fBQupgmkpO4SWPRjrxRWXEkEafZzwBTQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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