SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4ef859d9967060822cf531ed9ada5f0afbbbb21169469b8ee7b93028107525f' 
  AND token = '6wY6aoCAcUfugaNb89sY5zHXtZ3sDW45oiDzDv2SfWM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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