SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f3a8c369916f2a780d6e7372730b363e45a48b9af5f3992c8b8e6b21946b67fc' 
  AND token = '2eBSJDHiEYj40l+PUsfSxzGw9WcREtk1/BZ2TKYKRwg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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