SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ce01eb596879c28d8bdd56e4593eb8b16447a55deac2b0f9acc5a78d0ddd5b5f' 
  AND token = 'JqxVrsy+NBrK/MvW8uUBFae0lFngwAy0GqrN79B72FA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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