SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fdccf4f2656b3a33adaa8bdb65cbc83575934406699e67326d994e63d99a7171' 
  AND token = 'v4h2ZJWbR6CWtL+eM+/G+Ob1ANCepqmNXGpKgFFCeOg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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