SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'dce4a17aa44b3ecb46485fbb52b41403d1f950831736e9a8652b931f11cb782f' 
  AND token = 'rHVzC1JEma1IYf/9imFKwCVchif+yPJDWuE5fGX9rDc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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