SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '874e4cc47c91a58798923ec66cc44a890ad4efc8f462455470a13ad7b371997b' 
  AND token = 'YUUCdKL+HeBvNW+TYuxCi0qLJ6vhsZGYknxGRF9F47I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00046

JSON explain

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