SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20e093aeb9b8f27c3c9491101b2c8cd6919def16d4ac9d12782874f72f78fe2e' 
  AND token = 'XHDMeIGzgVbatKebC7YjnK0rvQXGtyh259tuwFB7ZqA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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